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Show Life Cycle of Thunderstorm Outlined by Bill Chapman and Staff, National Weather Service, Salt Lake City The life cycle of the thunderstorm has been carefully outlined to show how strong winds, heavier rainfall and lightning develop. Radar reports suggest the average time for such storm cycles to run about 20 to 30 minutes. Thus, heavy rainfall or high winds might strike one zone and completely skip over another just a few miles away along the storms path. This . is why one should keep a close watch on the sky for signs of thunderstorm development and movement at individual sites. Pilots, sailors and farmers have for years learned to keep a wary eye on the sky. Normally, a rapidly darkening turbulent appearing western or southwestern south-western sky, followedby distant lightning and thunder will give a hour or more advance notice of a storm's approach. Dust in the distance ahead of the storm will signal the onset of stronger gusty winds. Peak wind gusts of intense or severe thunderstorms strike quite abruptly and leave little time to secure campsites, campers or boats. American Falls Reservoir, Lake Tahoe, Great Salt Lake , Lake Powell and Lake Mead have often experienced peak gusts in excess of 60 MPH , with squall line thunderstorms. thun-derstorms. This is more than enough to turn over a camper, trailer, or upset a sailboat. Gusty high winds will rapidly generate in a matter of minutes waves in excess of six feet on shallow lakes or in narrow canyon-walled canyon-walled reservoirs such as Lake Powell. The water temperature of many higher mountain lakes can be so cold that it may paralyze, thus adding to the danger to boaters upset during stormy weather. Be Aware of Threatening Storms Outdoor recreationists should be particularly' concerned when thunderstorms thun-derstorms threaten their area. Above all, they should check the latest weather forecasts before going into remote areas which have minimal radio reception. Campers should avoid dry gulches during stormy periods. Heavy rainfall with thunderstorms many miles away,' could result in flash flooding in deep canyons or in usually dry gulches. A growing number of National Weather Service stations have continuous FM radio weather broadcasts transmitted on 162.55 or 162.40 megahertz. Many modern portable radios carry these weather trends. Check your location for these broadcasts. Avoid Lightning Hazards Lightning kills more people annually than tornadoes tor-nadoes and hurricanes combined. Only flash floods in recent years exceed the number of deaths by lightning. It usually kills just one person at a time, thus attracting less attention than more spectacular hurricanes and tornadoes. To avoid the hazards of lightning, move inside a large building or a metal vehicle. Do not stand ' beneath a natural lightning rod such as a large tree in an open area. Avoid projecting above the surrounding landscape. Avoid metal equipment and small isolated sheds in open areas. Boats on open water are highly susceptible to lightning strikes. Boats and swimmers should stay off 'the water during high thunderstorm , activity. In the open, campers should seek the lowest land level and individuals should drop to their knees and lean forward with hands on the knees. When Caught in a Thunderstorm Thun-derstorm If a boater is caught on a lake during a thunderstorm and cannot make it to a safe shoreline, he should go to a protective inlet or bay and hold the boat head on into the waves. Sailboats should also find a protective inlet, drop sail and anchor. Most larger sailboats can ride out moderate wave action. At the campsite secure all objects that can easily be blown about. If possible, park campers and trailers head on into the storm to minimize the overturning power of the stronger winds. When available, seek shelter of stronger buildings. Avoid lower stream beds that may flash flood from heavy rainfall. Make it Pleasant and Safe Whatever your intentions are for outdoor activity, the final results should be a rewarding and safe experience. ex-perience. Being aware of thunderstorms and knowing how to protect yourself from them will assure a pleasant and safe outdoor adventure. |