Dan Gudgel Warning Coordination Meteorologist
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There are many weather hazards that occur within the relatively benign Interior California region...and some of these are discussed much more frequently than others. During the summer months, desert and mountain flash floods are often a primary concern with locally heavy rain in showers and thunderstorms. In general, thunderstorms are the atmosphere's severe weather generator and a variety of hazardous weather occurs in and around them. In particular, lightning, hail, tornadoes, high wind, torrential rain, icing, turbulence, and lowered visibilities in rain and/or dust all occur with thunderstorms. One of the more interesting phenomenon that can occur with thunderstorms is that of snowfall that is possible even in the deep summer months because of our high terrain. It is often an overlooked hazard here in California. Such a case occurred on August 10, 1999, and was reported by Paul Judge while hiking in the John Muir Wilderness Area at 11,500 feet mean sea level. (The area is east of Yosemite and south of Mammoth Lakes.) Paul's family encountered a "severe electric storm" with "artillery barrage frequency." Because of the high altitude and the accompanying lower temperatures, precipitation occurred in the form of snow and hail, rather than rain. In about one hour a little more than 3 inches of snow fell. Obviously there is always danger from lightning with thunderstorms. However, the overlooked possibility of snow with a high terrain thunderstorm demands proper outdoor protective gear in the form of warm clothes and consideration for shelter from snow...even for hiking in California during the summer! Preparation for outdoor hiking should not only include those items necessary for personal needs and comfort, but also a NOAA Weather Radio. While it is difficult to forecast thundersnow, the development of thunderstorms is easily detected by modern meteorological tools such as the WSR-88D Doppler Weather Radar and high resolution satellite imagery. By weather radio, various weather warnings issued by the NWS can provide time-critical information along with Short Term Forecasts to prepare back-country hikers for inclement weather. Consider such a piece of equipment for your outdoor activities to keep you safe. Lastly, always remember that there are many dangers with thunderstorms and seek shelter with their approach. | |