10 June 2007

Strong and nervous at EFIK

This Sunday the ESV (Paragliders of Southern Finland) activists had decided to bring the ESV towing car to the Kiikala airfield (EFIK) in Southwest Finland. Kiikala is well known for its very reliable thermals, often conditions are really strong. Around 11 some 10 pilots had gathered at the airfield which welcomed them with a surprisingly strong notherly. Luckily the main Kiikala runway runs exactly norht-south. And some small cumulus were eagerly noticed. These developed quickly into nice clouds which also then dissolved quite quickly. Morevoer the clouds seemed reasonably high and didn't seem to move very fast. In short looked like an epic day!
Soon everything was ready and the early wind had calmed down significantly, indicating thermal activity. I was the the second pilot to be towed up. Halfway the tow it felt like I was in a thermal so I released, at 250 m AGL (above ground level). Sure enough I had caught a thermal, a bit weak so it required careful tracking but I slowly worked my way up and it didn't drift as much as we had expected. Above 600 m MSL (above mean sea level) it got stronger and better defined and a while later arrived at cloud base at approx. 2100 m. Interestingly further south, to where the wind was blowing me, cloudbase was clearly some 500 m lower.
I had taken off with Nummela airfield (EFNU) set as goal, but didn't know if that would work as it would require fighting a head- or crosswind. The upperlevel winds were some 10-15 km/h from the north so I decided to go with the flow until the big main road to Helsinki and then decide what to do next. Once I was there it looked like the upper winds had become less strong, and further south one could already clearly see seabreeze influence, so I decided to go east towards Nummela; sticking close to the main road to assure a quick and easy retrieve as I had to be home in time today.
After a mere 9 km or so encountered a strange phenomenon, a rather low cloud band formed a "wall", blocking the straight route to the east (see the picture). Above it was very high, strong cumulus that threatened to become a CuNimb (a thundercloud). As the forecast had warned for occasional local thunderstorms I quickly decided to stay away from this system. It looked liked I could fly around it on the north side, and as clouds looked good in that direction I changed direction to the north. But first had to work my way up again as I was getting really low. Now thermals were stronger though, a 4 m/s piped me up quickly. To my surprise lower down the wind was absent now, or slightly south. Higher up it was still north though. I glided a bit more north, going east didn't look attractive at all. After having gone some 8 km north I was a bit lower again, and down there the wind was clearly southwest now. I hit a realy strong thermal, but soon after that some real bad turbulence too. As the Kiikala airfield seemed within reach again I decided to leave the shitty air and go west. While flying straight west I actually was going up. After a little while not far form the airfield I noticed a few whiffs of moisture coming towards me from below. Within a mere 20 seconds these had formed a sizeble cloud below, and behind, me. I had barely escaped it by a mere 20 m or so, and felt a bit what it must have been like for the pilots in Australia that were quickly caught in clouds early in the year.
What seemed to be going on was that the southerly seabreeze was mixing with the main northerly at a layer between 900 and 1300 m MSL. Above that layer there was a nice convergence band; whereas in that layer things were really nasty. As I was now above this layer I could easily fly back to the airfield actually going up all the time until I was just west from the airfield. By now the turbulence and cloud threat was more than I'd like to encounter in a season, so when I hit some sink I quickly circled and spiralled down. Some 150 m above the airfield there was some more really bad turbulence, but I flew through it and then had nice constant sink in strong southerly winds and landed sound and safe 2:25 after take off, effectively having flown a square with sides 9km long. My friends in the field had seen my encounter with the cloud and the turbulence down low and none of them was eager to fly.... But were helpful in fetching me from the other side of the airfield and bring me back to our launch. Thanks!

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