Thursday, April 23, 2015

Not Where You Would Expect a Tornado

With much cooler air over much of the country this week has been rather quiet with respect to severe weather. Wednesday has been the most active day with a number of severe storms in northeastern Texas, including several weak tornadoes and hail to three inches.

On Tuesday there was a somewhat rare occurrence in the desert of southern California. A landspout tornado developed out of an isolated thunderstorm and caused some damage to a solar panel array near Desert Center, CA, near the California-Arizona border. If you're wondering what a "landspout tornado" is, it's a tornado that is not associated with a mesocyclone or rotating thunderstorm. They are typically weaker and smaller than tornadoes associated with a supercell and tend to have a smooth appearance, similar to a waterspout (hence the name "landspout"). It is a tornado because the rotating column of air is in contact with the ground and with the parent cumulonimbus cloud - the definition of a tornado.

Landspout tornado near Desert Center, Ca on April 21.
Photo via NWS Phoenix Facebook

The tornado was first reported by a pilot flying in the area. The circulation associated with the tornado was not evident on radar since it was at low levels. The nearest radar was in Yuma, AZ, and at the distance the radar beam at the location of the storm is at about 10,000 feet above the ground. A news crew and a number of other people were able to capture photographs of the tornado.

Another photograph of the Desert Center landspout.
Photo by Russell Fischer via Facebook.

This is the radar image of the storm at 4:00 PDT, about 13 minutes after the tornado was first reported by the pilot. This was at the storm's peak strength. Fifteen minutes later the storm had weakened considerably. The tornado icon indicates where the tornado was reported.
Based on early reports of damage, mostly to the solar array, the National Weather Service has preliminarily given this a rating of EF0. A number of panels were bent and twisted and others were damaged by rocks and other debris flung about by the tornado.

Solar panels damaged by the landspout

The NWS will be sending out a team to survey the damage in a few days. A description of this tornado, photos, and maps can be found at the NWS Phoenix web site.

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