rodbailey

Clouds
by Dixon White ( http://eagleparagliding.com )

This is the 5th article in a series on weather and flying pointers. Contact me or the USHGA for the previous articles which are important for following the thread of these discussions. Remember that practice is the mother of skill and get to the park frequently to refine your ground handling - remember to kite in the a forward facing position, for best glider integration training. Study the tests you originally took from the USHGA to stay current in your modeling. Do your own homework on the weather and make your own decisions on whether to fly - you're the one who gets to either enjoy the flight or suffer through it.

The "K" index makes an attempt to "rate" the possibility of thunderstorms. An index of 15 is low and 40 is high. We want to avoid flying in conditions where thunderstorms are likely. If you note that cumulous clouds are starting to billow taller than they are wide you may expect strong areas of lift and sink that may exceed your abilities to manage turbulence. Growing cumulous can create such strong lift that you may become trapped in the cloud, which is illegal, cold, disorienting and can lead to hypoxia. Some cumulous clouds can be 10's of thousands of feet in height. Even if rain or virga is miles away it can create sudden gust fronts (called "out-flow boundaries" by the NWS). Virga, which is rain that doesn't fall all the way to the ground because of evaporation, can create strong gust fronts because the chilled air falls to the ground and flows outwardly. Keep in mind that a cloud dropping virga or rain as much as 10 miles away from your flying site can cause high winds. Virga looks like a veil or can appear wispy.

When studying the underside of cumulous clouds or a layer of clouds, "stratus", look for lumpiness, called "mammatus", in addition to virga. These can indicate the possibility of impending rain. To fly uneventfully shouldn't mean you survived a potentially dangerous situation, it means you've learned to anticipate what may happen and then either choose not to fly or to land to avoid flying under duress. You wouldn't knowingly walk across a thin layer of ice, don't fly in conditions that are clearly dangerous. Your accident could shut down a flying site.

The weather section of www.paraglide.com was recently improved to help you follow a step by step process of making weather evaluations. You may need to adjust some of the sections to specify your local flying area.