Tooele Transcript Bulletin – News in Tooele, Utah

July 27, 2022
Friday’s microburst in Erda caused significant damage

Microburst, landspouts and tornadoes 

Localized high winds struck part of the Erda area on Friday damaging irrigation equipment, homes and fences.

The National Weather Service declared the cause of the winds to be a microburst. They posted video from the Alert wildfire camera on Farnsworth Peak showing the formation of the microburst and the spread and dissipation of the downdraft crossing Erda.

The NWS describes a microburst as a localized column of sinking air, or downdraft. They are usually less than or equal to 2.5 miles in diameter. 

Microbursts can cause extensive damage at the surface, and in some instances, can be life-threatening., warns the NWS.

As the result of cooling within a thunderstorm, the core plummets to the ground. As it hits the ground it spreads out in all directions. The location in which the microburst first hits the ground experiences the highest winds and greatest damage.

Wind speeds in microbursts can reach up to 100 mph, or even higher, which is a speed equivalent to an EF-1 tornado! Winds this high can cause major damage to homes and other structures and level hundreds of trees. 

Reports from observers on the ground in Erda reported damages to large trees, irrigation equipment, roof shingles blown off, play structures damaged and blown over, damage to fences and damage to houses under construction.

The reported damages indicate that the wind speed may have reached up to 70 mph in some areas of the microburst.

Earlier in July, the NWS identified landspout tornadoes in part of Tooele County west of Grantsville.

There are two types of tornadoes: those associated with supercell thunderstorms, and those that are not, according to the NWS.

A landspout tornado not associated with a supercell storm. Landspouts have a narrow, rope-like condensation funnel that forms while the thunderstorm cloud is still growing and there is no rotating updraft. The spinning motion originates near the ground and is stretched upward.

Landspout tornadoes tend to be much weaker and shorter lived than their supercell counterparts, with wind speeds rarely exceeding 100 mph.

Supercell tornadoes include the “Wizard of Oz” type tornado. The spinning motion originates in the storm and descends downward creating the typical spinning funnel appearance. 

Supercell tornadoes are capable of completely destroying well-made structures, uprooting trees, and hurling objects through the air like deadly missiles, according to the NWS.

The National Oceanic and Atmospheric Administration lists five tornadoes in Tooele County from 1950 to the present in their storm events database. Those tornadoes took place in June 1965, August 1965, May 1968, July 1991 and May 1993.

The 1991 and 1993 tornadoes were listed as F1 in magnitude. An F1 tornado is described as a “moderate tornado” with winds from 73-112 mph. An F1 tornado may peel the surface off roofs, push mobile homes off their foundations or overturn them, push cars off the roads and attached garages may be destroyed.

The May 1993 tornado destroyed the movie screen at the Motor Vu Drive In.

 

Tim Gillie

Editor at Tooele Transcript Bulletin
Tim has been writing for the Transcript Bulletin since October 2017. In February 2019 he was named as editor. In addition to being editor, Tim continues to write about Tooele County government, education, business, real estate, housing, politics and the state Legislature.A native of Washington state and a graduate of Central Washington University, Tim became a journalist after a 20 year career with the Boy Scouts of America.

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