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Ed Yeates ReportingMeteorologists say the storm disaster that tore apart portions of Salt Lake and Utah County three months ago was a rarity. Randy Graham told his colleagues today it's just another example of how difficult it is sometimes to forecast weather along the Wasatch Front.
I'm not a meteorologist so this is pretty simple. On August first, Nature was concocting a recipe we don't see often in this valley -- wind speed, a cold front, unstable air, convection, the mountain slopes and thunderstorms, and BOOM!
In meteorological terms a severe bow echo, as its called, hit portions of Salt Lake County while leaving other areas untouched. Then moments later another bow echo formed only to hit Utah County.
Randy Graham, National Weather Service, Salt Lake City: "The intensity of the storms that impacted the Wasatch Front on August first was unusual. And to have two of them impact the Wasatch Front the same day would definitely be a rare event."
But back to a more detailed recipe of what caused all this. As Randy Graham told his colleagues at a University of Utah workshop today, it's another example of why forecasting in this topography along the Wasatch Front is so difficult.
Randy Graham: "The cold air gets blocked by the mountains as the system crosses the mountain range. And that's what happens, a portion of the cold air descends the east slope of the mountains and reforms a new line of severe thunderstorms very rapidly. And the system just keeps going."
In just a short time in those morning hours of August first, the thunderstorm complexes in bow shape forms hit and hit hard, leaving behind 13 million dollars in damage.
Randy Graham: "The extent of the damage and the strength of the winds, particularly in Provo, was pretty exceptional and pretty rare."
Forecasting out of the box, that's what meteorologists say you have to do in this complicated topography.
Alex Tardy: "We need to expand like our tool box. We need to expand what one uses to access and forecast the weather."
Tardy says in storms like this meteorologists no more can just rely on conventional weather stats and climatology. They can't stay in a comfort zone, typical of areas where forecasting really is predictable.
Alex Tardy: "Really consider other options that might happen, other scenarios that might happen, in order to forecast these events that are not so common."
