Friday, August 30, 2019

High Impact Weather Overnight

In yesterday's post we discussed the possibility that thunderstorms could affect the Holy War and indeed that happened.  It was fortunate that kickoff happened without a hitch.  Just before kickoff, a moderate precipitation cell passed across Utah Lake and just south of Provo.  It produced one detected lightning strike just west of the southern tip of Utah Lake.  I grabbed a couple of screenshots on my phone while watching the start of the game. 

Source: RadarNow!

Then, in the 4th quarter, another cell moved in and produced a strike about 2.5 miles south of LaVell Edwards Stadium. 

Source: RadarNow!

NCAA policy requires play to be suspended for 30 minutes when lightning is within 8 miles of a stadium.  An already late game became even later.  At least it prolonged the suffering of fans of that school down south. 

Moving on to more serious matters, media reports (e.g., this one from KUTV) suggest that a fire sparked near Bountiful at around 1 AM during a thunderstorm.  The fire spread rapidly, burning 150 acres, destroying at least 3 homes, damaging others, and requiring evacuations along the Bountiful–Centerville east bench.  Despite being called the Gun Range Fire, it sounds like the fire was lightning sparked, although I have not seen official confirmation of this (please post if you have official information). 

Whether human or lightning caused, the situation last night is an example of how fast things can go downhill in the urban-wildland interface.  It was probably minutes from fire spark to dangerous fire spread, requiring evacuations with no warning in the middle of the night.  The thunderstorm last simply provided a lightning strike in the wrong place with little to no precipitation, low humidity, and strong microburst winds, which is a recipe for rapid fire spread.  Indeed, observations from the Bountiful Bench show strong sustained winds likely associated with a microburst or thunderstorm outflow peaking at about 30 mph just after 1 am.  These winds were out of the east, which is favorable for driving a wildland fire sparked above Bountiful or Centerville into the urban interface. 

Source: Mesowest
Fortunately winds died down shortly thereafter, which should allow fire crews to get a handle on things, but not before damage was done.

I can tell you that such a scenario is what concerns me greatly about living near the urban-wildland interface.  What happened last night could easily occur, for example, in the Avenues.  A dry thunderstorm sparks a fire just above 18th Avenue and northerly microburst winds fan the fire directly into the upper Aves.  The fire would threaten homes and residents with little or no warning.  Alternatively, a human caused fire in high winds causes rapid fire spread, as occurred last summer near Ensign Peak.  It's worth a look at Calfire's website that discusses how to prepare for wildfire if you live in such an area. 

1 comment:

  1. Fire was caused by a campfire left burning. I suspect it became a problem when the thunderstorm's winds moved in, though I haven't seen official confirmation of this.