The Gliding Series

 Storms

Storms are dangerous. They can kill and they often do. This is not a general description of storms but a few selected topics from wartime flying, gliding, some background philosophy and some personal experience. Maybe some lessons for the thoughtful.

There is a monument at the entrance to Carnarvon National Park - an aircraft wing standing upright. It is from an American aircraft - metal as we use today - that was wrecked by a storm on a simple cross country flight in our outback. All killed. And such an aircraft would have a higher  strength than, say, a 747: That is, put rather crudely, a higher G load to structural failure. Be it a Spitfire, a glider, a modern airliner - storms can always win.  They often do.

Storms are simply one aspect of weather and as such should not be too separated from our understanding of weather generally. Storms can be forecast - or mostly they can be - but forecasting can be imprecise or faulty, or simply unavailable. Nothing can replace experience but we cannot always decide upon the experience we should have. Storms themselves vary. They can be isolated, in lines, associated with weather patterns, triggered by physical features, be the so called ‘dry’ variety, spawn tornadoes, have low cloud associations or show surprisingly little cloud, vary in colour leading up to the terrible brown storms, have associated with them the smoothest of lift or be turbulent to structural failure, have invisible (or wonderfully visible) rolls - and so we could go on.

Storm characteristics do vary with the part of the world we are in. If we take the ‘gliding’ area west of the Divide from The Downs to Victoria   we can certainly have storms but they are not normally a real worry to the wary glider pilot. Go further west and north into the tropical or monsoon area and we have - well - the monument at the park entrance. There are of course storms in England   and  Europe and  they can be severe but usually they are not in comparison with elsewhere. During the war there was the incredible effective ( from our point of view) firestorm series of bombing raids on Hamburg . Potential for storms. Potential for firestorms from concentrated bombing  as at Hamburg and later, Dresden . First night at Hamburg and conditions suited the bombers. Next night the storms played merry hell with the aircraft but not quite, in most cases, to the structural failure stage. And, it is said, storms were only to about 20,000 feet. Babies, in comparison with the 80,000 plus heights of elsewhere. If we move to USA we now see on TV the terrible storms and lightning and tornadoes  they have in the central west. I will save the Asian monsoons for later.

For an understanding of storms a pilot needs theoretical knowledge of storm formation and structure - an understanding of lapse rate - of the dry adiabatic lapse rate - of condensation level- of weather pattern movement. Then of course for the storm itself we have ice, hail, lightning. Updraft and downdraft. The smooth outflow and lift area, turbulent areas, the roll area or cloud. But all this should fit into a general weather knowledge. Limited knowledge can be dangerous.

The fortunate pilot is introduced to storms gradually - later, actually, after a knowledge and appreciation of weather has already been built up. Luck of the draw in a way - and I made a very lucky and interesting draw. Let me expand. I began by doing over a year of training in roughly what I have described as the gliding area. As it was training many weather decisions were made for me and as I gained training experience I was exposed to more and more weather. But rather soft weather. Then the move to England and another year or more of further training and actual first pilot experience. A vastly different type of weather that introduced me to bad weather flying but not really of the storm type. A background weather experience that served as a suitable introduction for what was to come later.

Let me leave storms for a while, and move to the pilot. A pilot of course needs training and experience. Training is not experience - experience comes later: But in most cases even experience has its limitations. And the weather in which a pilot flies has its patterns quite apart from what we might call the regular  local climatic patterns. But let us move to real life. And a  few comparisons or stories.

Waikerie South Australia . World competition glider pilots. One from England . In conversation he mentioned - the village to the east about twelve miles away. Twelve miles? No - it was about forty. He was judging with his very extensive English flying experience. But don’t let us only pick on the Poms. Wartime. Wartime trained pilots with eight full months of  training. Air Force pilots with wings. Air Force training - not Saturday afternoon flying. On a number of occasions I would have my little joke with them when as instructor I would take them up on their first (air experience) flight in England . A look at the English countryside. Experiencing a new aircraft type. A typical very hazy English day. Almost a fun flight. I would end them up on the downwind leg with the aerodrome in position on their side - correct heading - correct height. Then tell them  - right, we’re in the circuit. You try the landing. Quite often they simply could not ‘see’ the airport. There it was large as life and their unaccustomed eyes could not ‘see’ it through the incredible complexity of the English countryside after the sparse easy to follow Australian countryside. But in no time flat they would be quite at home flying in England .

These pilots were not over-confident - exactly the opposite. English countryside was a new and surprising experience - the countryside and the poor  hazy visibility. Overconfidence even when combined with training and experience can be another aspect. A thousand hours of flying in England with its confused countryside, its smoggy conditions when on occasions the ground becomes invisible from 3000 feet, its low cloud base of a hundred feet. Then to India - what are these local pilots on about with weather after English weather? The pilot I am thinking about (and it was not me) did not take long to learn.

Another aspect before we get back to our storms. There is a certain ‘in between’ condition when we consider area climate and short time  associated weather variability. We can have what I will call periodic weather. A dry spell of quite a few years. Wet periods. 

In the sixties we had a number of successive years with specific storm conditions over the Downs and the South-East. Doubtless even beyond as well. As summer approached the weather was often stormy. Afternoon, fairly scattered  isolated or line storms. We ‘learned’ certain habits. Watch things on cross country flights but some very interesting cross country flights were still possible. Carry on with the training circuits but be ready to pack up quickly and get the gliders hangared. For an hour or so at least. We developed a ‘safety’ procedure. Most storms were pretty obvious - nothing unusual about that - but I can recall two days when we had what I will call dry storms. The weather change was there to see but  - well, it didn’t really look like a storm. But on two occasions a glider doing a circuit suddenly found it was being ‘blown down wind’ and simply could not complete its circuits. Blown away before the ‘storm’ and luckily, in both cases to a paddock landing a few miles away. But more detail on those flights shortly. 

And something else too. When to pack up and hanger the gliders?  I recall once at Oakey when  Daphne and I were flying the Hutter privately and the Oakey Club were doing club flying. Yes, storms about but not yet time to pack up. Or was it?  Local knowledge told the Club members that a certain storm would miss the aerodrome.  But they were neglecting one recently published bit of knowledge. I knew of it and put the Hutter away. They continued to rely on their “local experience’ and as a result had their glider damaged trying to get it off the field and into the hanger  when the storm did pass over the aerodrome itself.  My ‘extra’ piece of knowledge came as a result of a series of experiments carried out by the Met section of the Department of Civil Aviation - storm experiments on the Darling Downs. I will move on to that too  but one final bit of general comment.

The sixties moved on and the stormy weather cycle moved on too. A new generation of glider pilots grew up who had little ‘storm’ experience and almost laughed at us old timers who warned of a storm danger when we saw such a danger as a possibility. The ‘new’ pilots had to learn the lessons for themselves. I don’t recall saying though - ‘Told you so’. What is that background word so important in the education of a pilot? - AIRMANSHIP - a broad and very important concept. Anyway, lets move to the Downs Weather experiments. That will get us back to storms themselves. “Glider weather’ first and wartime later.  

Gliding Weather:

It could be a good day. Isolated fair weather Cu or better still, maybe it could be streets of these Cu. Maybe very smooth - perhaps a little rough. Depending on the lapse rate picture we could also have towering Cu. Not thunderstorms but tops at  12, maybe 15, maybe even over 30,000. Again, smooth or rough  but this  not specifically related to height. Turbulence can vary. I can recall one fantastic day approaching Narromine from the north where I took only about every third thermal, one turn and I was centered on smooth 1000fpm lift. And the opposite - again in the clear - when I could demonstrate to a pupil how almost ineffective the controls could become under a good Cu - and of course worse if we had illegally gone in. There can be terrible turbulence in a Cu at, say, 12000. But again, I can recall a climb in a towering Cu near Inverell where the lift was smooth. And powerful. I had elected to come out at about 20,000 and turned on to my pre planned escape heading. I gained another 3000 on the way out and saw the tops were over 30,000. Why not go higher? Basically then there were two types of oxygen masks. I did not have the ‘better’ type recommended for 30,000 and above. But we are really concerned here with storms. Storms can look bad but they can also be deceptive in appearance. I will recount now an extract from a write-up I did in the sixties. It was called Sailplane Meteorology -- without tears.

Late evening storms had been forecast. Throughout the day, although there had been an abundance of ragged Cu, lift had been very weak. Even the Grunau, which can usually stay up on a puff, managed only a bare twenty minutes. The ground was very wet from almost a week of rain.

About 4pm the Hutter was launched, after the Kookaburra had done a circuit without contacting lift. Those at the aircraft end noticed a heavy cloud to the left with a misty scud in turbulent movement well below the main cloud base. Those at the winch saw the pilot contact lift to the right near a similar but separate cloud. It soon became obvious to them that the pilot was having great difficulty controlling the aircraft. About this time those at the winch end heard a sound like rain and saw trees and corn in the distance in violent agitation. Soon the wind (for wind it was and not rain) arrived. It blew at 25-30 mph almost down wind compared with the launch direction. This immediately and effectively stopped launching. Meanwhile the Hutter got further and further away and eventually was seen to make an approach into a paddock about four miles from the strip. To this time there had been no thunder, lightning or rain. Within the next hour small isolated storms passed through the district in fairly rapid succession, but no rain fell on the aerodrome or where the glider had landed.

Another time. The sailplane pilot reported smooth and increasing lift off the launch. This lift suddenly became turbulent and scuds were noticed forming at the sailplane height of about 2000 feet. Turbulence became so severe the pilot was barely able to maintain control.. The ‘g’ meter, fitted as a permanent instrument to this aircraft, fluctuated between -1.5 and +3 g; dust remained suspended before the pilot’s eyes. He noticed the strong wind change and turned down wind out of the turbulence, drifting rapidly away from the field. Several later attempts to return again produced severe turbulence and it became a case of getting down somewhere in a paddock. This sailplane was not equipped with spoilers and the pilot found himself in the unusual position of being unable to lose height even with as much speed on the clock as he dared.  Paddock after paddock disappeared beneath him, and after quite a few beats across wind at 800 feet, a safe landing was made.  The pilot reported it was his most frightening flight ever. ( I was not the pilot on any of these flights!)

Next day, at about 1.30 pm three heavy storms could be seen from the field. The Grunau was soaring and as one storm seemed to be approaching the aerodrome all aircraft except the Kookaburra were hangared. Very heavy rain looked 6-8 miles away when the wind changed, thus preventing the launch of the Kookaburra. The Grunau at this time was about 1500 over the strip. It lost height slowly and looked to those on the ground to be setting up for a ‘normal’ circuit, which would have meant a 25 mph downwind landing. At about 300 feet he made a change of direction and even though it was obvious to those on the ground control was difficult, he made a safe landing into wind.  The pilot reported that at first he thought  he had found a smooth evening thermal but turbulence, when it came, had him afraid of structural failure. His concern was to try to get down safely - anywhere.

On another occasion the Kookaburra launched with a storm nearby. Those on the ground noticed a strange wind change when the plane was about 200 feet. The pilot reported a normal launch into lift and an immediate climb to 3000 feet. The previously smooth lift then became turbulent. He applied spoilers, lost height rapidly, and landed safely in the strong wind period to the commencement of heavy rain.

These few years of peculiar storm conditions passed and as I said earlier, later pilots 'poo-hooed' advice of the lessons learned. What are the lessons? Let us look now at what I will call - The Anatomy of Thunder Storms.

Our representative storm cell has grown out of a towering cumulus cloud with its cauliflower top. An anvil blows out ahead of it at the top gradually shading the area ahead. The whole cell moves across the countryside blown by a lower but also upper wind. It has grown well above freezing level which will vary mainly with latitude but also with atmospheric conditions. On the Darling Downs it will often be about 12,000 feet. There will be a strong area of lift inside the cloud itself and behind that a downdraft area. The updraft and downdraft will be essentially side by side. In India we were quoted possible speeds of 100 mph. I have seen that figure corrected after later post war research. Two hundred miles per hour was given.

On the ground ahead of the cell the wind will often be light blowing  towards the cell. Thus aircraft can be taking off into a light wind flying away from the storm. Suddenly though there will arrive an extremely powerful and turbulent downdraft wind ahead of the cell. A wind reversal as far as the pilot is concerned. Just ahead of the cloud itself at about cloud base these two opposing winds can form a roll. Though usually invisible at times it can appear as a most spectacular roll cloud. And this - visible or otherwise- can  be catastrophic for a pilot. Once a pilot has actually seen a roll cloud he needs no further advice on the dangers near storms.

The diagrams that follow are from notes written in the sixties - line drawings from research information - and obviously before the days of electronic reproduction.

Radar picks up cells from which rain is falling. 

The two diagrams below show actual radar echoes for a squall line and random storms ...

Recent investigations were made into storms on the Darling Downs by the meteorological Office, Brisbane. While it would be unwise to apply the findings ‘as is’ to all areas, many findings will hold good as a general rule.  Of about 100 storms studied, one fifth occurred in general rain conditions and as such would not normally affect the sailplane pilot. One fifth had short paths of less than 20 miles,  but about half had paths of more than 20 miles.

Locals will often say, "our storms come from that direction" or "any storm you see there won’t come here". The Darling Downs investigation showed that almost all of the 100 storms studied did come from a certain 120 degrees of the compass (in this case 180 to 300 degrees). 

The investigators were naturally reluctant to draw definite conclusions from such a short series and they did draw attention to the fact  that ground estimates of paths are frequently unreliable. An attempt was made to relate storm movement to an upper wind level. In work done in Florida in 1949 over 95% of storm movement agreed with the 12,000 foot wind. Agreement on the Downs with winds at Brisbane (nearest available)  also gave a high agreement but at a lower percentage with the 10-15,000 foot wind. Speed of storm movement was slower than the wind speed.

From the rainfall results of actual random type storms it appears most are 4-10 miles wide. This points to the fact a glider may be able to make a safe landing to one side of the storm. In the figures below, rainfall results show the extent and path of random storms. Gliders could be doing cross country flying in such storm conditions.

Obviously a storm may consist of more than one cell. A number of cells may form one large cloud and the life of the cloud may be prolonged, with each cell having a life of about half an hour.

While people usually associate the arrival of a storm with the commencement of heavy rain, the storm has arrived, as far as the sailplane pilot is concerned, four to ten miles ahead of this, and 15 to 20 minutes before. 

Smooth lift is experienced at height before those on the ground become aware of the wind change. When lift is experienced the ground is often in full shadow. Because of the cell cycle danger can exist well before the advent of thunder or lightning. It is repeating the obvious to say that the roll area is a source of high danger whether it is cloud visible or not.

The wind reversal, when it comes, can be sudden and strong. Ground handling is difficult. The diagrams emphasise the first gust danger and its severity.  

I will conclude this section with some extra findings of the Darling Downs storm observations. During a 127 day period there were 56 storm days. Of these 32 were line storms, 6 were along surface fronts, 19 were ahead of surface cold fronts and 7 apparently had no connection  with surface fronts. In the squall line zone ahead of the cold front, several roughly parallel lines of storms were observed, although it was not found possible to distinguish the lines from the ordinary synoptic weather charts. The lines examined had an average length of over 100 miles and were 36 miles wide. The squall line is not always parallel to the front line and of the cases examined varied up to 60 degrees from the front line.  The squall line may persist for up to 24 hours and move hundreds of miles in that time. The squall lines consist of cells as described previously.

But let us leave peace time Australia now and go back to the World War II period.  

Wartime Weather:

Of course there are storms in England and Europe . On very rare occasions England can have a tornado. But I will put English ‘bad weather’ into context this way. After the initial shock of experiencing average English weather after the ‘nice’ Australian weather we trained in, many of us grew almost to like the poor visibility hazy days. Those of us involved with Beam instruction (landing in low cloud conditions using radio beam systems ) literally rubbed our hands in glee when we struck a ‘real’ day with a cloud base of 100 feet. But after falling in love almost,  with the bad but soft English weather we entered a new world with the weather of India and Burma.

Almost a thousand hours of wartime England first pilot. Flying a Mosquito from England , across North Africa, and into Asia. Then the initial Squadron  briefing at Calcutta. Forget about previous weather experience. Soon, it will be the monsoon. Rain you’ve never experienced. Well, yes, very heavy. It will take the paint off your aircraft. And peel the fabric cover over the under wing top surface. But that will not be the real worry. There will be storms. Long lines along the coasts you will have to cross going and coming - Burma, the Malay Peninsula. And other storms as you fly over Siam and perhaps China (no storm detecting radar in those days.) You enjoy cloud flying? Well here you stay out of cloud if at all possible. Your aircraft that will take you easily to 40,000 feet won’t get you over them and will break up in them.

We were told we would not be able to tell the difference between blue sky and black cloud. Maybe, we thought but it was right and it did happen to me. I was pretty sure it was a clear space in the distance to use but no - it WAS black cloud ... and worse still, we were told, was the brown storm. Later I was to agree with that. We were also told of the Spitfire pilot who entered a storm and found himself in his seat with no aircraft round him. He did  parachute down OK, we were told. A good story we felt, and obviously embellished to impress. More on that story later.

So the monsoon came and so did the weather and the storms. I will quote now a number of extracts from my wartime write-up - "This Man’s War". 

19/4/45 ... I noted in my diary: F\Lt........... did not arrive from Cox’s. They searched with the Harvard in the morning. We are on tomorrow. We flew low as prescribed searching, two miles south of track but no sign. Time for a swim.  The Squadron was based at Alipore, Calcutta . After a briefing we would take off some time after lunch and fly to an aerodrome on the coast to be ready for a trip (an op as it was called) the next day. We used a forward base, and this shifted forward as we gained ground against the Japs. At this time we used Cox’s Bazaar, in present day Bangladesh . If we were early enough we could go for a swim in the Bay of Bengal . We would fly our op and, after refuelling, would return to Alipore. This out and return section was across the Sundabans, the 300 mile wide delta of the Ganges and Bramaputra Rivers - flat, swampy, mangrove covered, settled in a few isolated spots. We each got to know certain islands and spots on track on this run. By this time - April - storms were beginning to worry us - make us alter course to avoid them.

20/4/45 ... again from my diary: No. 9. Off just after six. There was a little stratus on the way. It was clear over Bangkok for the bomb damage assessment. The Liberators had paid Bangkok a visit the day before. Smoke rising but got Bangkok OK . Then we followed  a canal, photographing it, and also took a bridge for BDA. No good for mapping survey. We took coverage for map making which had to be in the clear from 25,000 feet. Saw what looked like a dump and took it from 9500. Alto-stratus clouded over 10/10. It was 10/10 then, not 8/8 as now. Time 6.50.

After refuelling at Cox’s, I flew back to Alipore with the weather very stormy indeed. ‘Very stormy indeed’ was quite an understatement. It was one of those ‘brown storms’ we had been warned about. Hell, it looked terrible, and right on our track. I deviated east and flew around it.

Next I got involved in flying the C.O. to Kashmir for leave. I was one of the second dickies. That took a couple of days. Meantime the wreck of the missing plane had been found. There is a common saying for someone who is exactly on track - dead on track. Unfortunately it was for real this time. It was on a mangrove island that had a particular shape and one some of us used to check our track. 

29/4/45: I did an op to Southern China flying there direct from Alipore and landing at Cox's on the way back to refuel. Between Cox's and base we had a look at the wreck. It was hard to spot but we knew exactly where to look. It did not look as though he had been trying to ditch as the aircraft faced inwards under the mangroves just off the water’s edge. It appeared remarkably whole.

Many years later, after gliding experience, maybe the penny dropped about this prang. It was exactly where my brown storm had been but one day different. Glider flying at competition level entails weather knowledge. I noticed this -- Similar weather patterns regularly occur. With many weather patterns Cu clouds and Cu Nimb clouds are part of the pattern. I noticed that such clouds tend to form in exactly the same place. Of course such clouds grow and die - but often in the same place. One turning point may consistently be bad while another will have helpful lift or clouds above. Common weather patterns in exactly the same place. Today could be the same as yesterday - or tomorrow. So there is a chance he got mixed up in a brown storm  perhaps just at formation stage. Such a cloud could literally flatten an aircraft against the ground. Perhaps we are moving into the post war micro burst situation.

Back to wartime. So I watched storms as the weather (and the storms) got worse. 

17/5/45 ... a diary comment: Had a bad time in a storm. Maybe he doesn’t treat them with as much respect as I do. 

12/5/45 ... a diary comment from an op: Off to Bangkok again with a lot of cloud on the way. Some along the Burma Peninsula and the largest Cu Nimb I have ever seen. I was at 33,000 and I wasn’t even half way up it. 

4/6/45 ... my diary write-up for another op: Rain in the night so slept in a little. Saw flying control and arranged to take off  from the short runway using the extra 200 yards of taxiway. It went quite OK. Full load and 25 degrees of flap. Also we were taking off over the sea. We were forced to climb in the wrong direction - back towards Akyab and then go well south steering 210, 175, then 100 degrees. Crossed the delta and at 20,000 were getting ice in the stratus.  Struck a wall edge of Cu Nimb from a front along the mainland so we gave it away. Used headings from Akyab and set course for base.  Paint (dope) and fabric strips over the ply peeling off the wings. Didn’t like it.

25/7/45 ... another diary entry: Fourth wedding anniversary - what a day. It rained from 2 am till 8. Seven inches and the aerodrome unserviceable. The op. was therefore off. Rained off and on all day. There was a worried Spitfire pilot. He flew through bad weather and when he landed saw his prop was in a mess.  Apparently the five bladed prop is wood with a fabric and hardened dope cover.  It was all in tatters. 

26/7/45: Tried to get off in the afternoon but another Spitfire pranged and blocked the runway.  Will try to return to base tomorrow.

27/7/45:  Off at 9.15 and needed all the runway, just clearing the trees. Fabric coming off the wings. Showers all round but weaved in between them. We were able to climb and every now and again sneak through gaps. Turned the transfer cock on and blew 200 unwanted gallons from the drops. From my navigator’s plot we flew 270, 180, 330, 265, 360 to make a track of 300 degrees. Got back OK. And so the flying goes on.

Bad weather flying but I avoided the storms. Some did not. I will conclude with two other episodes. 

Many years after the war I found written up in a book the episode of the Spitfire we were warned had broken up in cloud. I will now quote it and add another storm flight from Burma.

From "Above All Unseen" by Edward Leaf 1997 ISBN 1 85260 528 6 page 160 ...

as he returned to Chittagong from a sortie over central Burma W/0 EDC Brown of the RNZAF flying a 681 Squadron Spitfire PR IV was faced with a mighty bank of cloud. With insufficient fuel to fly around it, he had no option but to dive straight through it.  Having gone into a spin and blacked out, W/0 Brown suddenly found his aircraft disintegrating around him. Somehow he managed to pull his ripcord and land safely but it was later found he had fractured his spine.

From the magazine "Mossie" No.26 Summer 2000 at page22 ... a report by Squadron Leader C. L. Gotch of 82 Squadron operating Mosquitos out of Kumbhirgram (Assam, India) ... 

To reach the operational area, the Chin Hills rising to 9000 feet had to be negotiated first. The clouds over the mountains were just one of the hazards. On the night of 10th February 1945, I took off on an operational sortie at 2000 hours. At briefing we had been warned by the Met. Officer that the weather was not good and that on no account was it safe to enter cloud. ... this instruction was always difficult to accede to. Knowing that I had to climb to approximately 15,000 feet to climb over the cloud tops, I decided to make height over base to at least 10,000 feet. It was a dark night with no moon, but seeing some broken patches above, I tried to find a gap through which to climb. At 8,000 feet while heading for a gap I found myself in cloud without warning. The bumpy conditions were immediately so severe, that I had no apparent control of the aircraft. Relying solely on instruments, I saw that the artificial horizon was showing the aircraft upside down. I carried out the normal correction as best I could. The aircraft then stalled, the ASI showing 80 mph and the rate of dive 4,000 feet per minute. What happened next is extremely confused, but after being in cloud for not more than two minutes I found myself in a gap at 13,000 feet with the cloud continuous above me to at least 16,000 feet. Seeing the airfield lights below, I dived immediately, and landed straight away. I consider myself extraordinarily lucky to have come out of the incident alive. Just before coming out of cloud I had told my navigator to prepare to bale out as I had no control of the aircraft at all. I have given strict instructions to all aircrew in my Flight not to attempt to fly near cloud at night and on no account to enter Cu cloud at any time during the day or night.

 > Return to "INDEX"