Friday, November 22, 2013

The Return of the Big Bad Wolf and Meteorological Zombies

We are currently in a "lull" with regards to the strength of the downslope winds, but the Big Bad Wolf is expected to regain his lung capacity with the winds expected to intensify later today.  The National Weather Service has thus extended the high wind warning to noon Saturday.

Source: NWS
Gusts yesterday fell short of those observed in the 1 December 2011 event, but nonetheless were impressive and caused problems for travel by high profile vehicles along the Legacy Parkway and I-15.  The highest gusts (80 mph) were observed in the Centerville–Farmington area.  The 62 mph gust at the University of Utah is quite impressive.  I can't recall what our record is (maybe ~70 mph), but I always use 60 mph as the threshold for a significant event.

Source: NWS
Strong easterly winds along the Wasatch Front come in two major varieties:

  1. Gap winds or thermally driven exit jets that emanate from deep canyons like Parley's and Weber.  These winds tend to be confined to very near the canyon mouths and occur fairly frequently.  
  2. Downslope winds associated with flow across the Wasatch Crest and the development of high amplitude mountain waves.  These winds occur less frequently, but can be much stronger and and affect a larger area.  
Unfortunately, the term Canyon Winds, which makes some sense as a name for the former, continues to be used for the latter.  Yup, this is Zombie meteorology.  No matter how hard we try to kill Canyon Winds as a name for downslope wind events, it goes on like the living dead. 


  1. I saw Eubank talking about the "canyon winds". I think local news weathermen need to leave scientific explanations up to scientists and just give the forecast provided by the NWS. Otherwise, we end up with the spread of pseudoscience, which only works against educating a generally scientifically illiterate public.

    1. On those lines, I think the High Wind Warning says exactly what needs to be said: strong east winds will affect Davis and Weber counties tonight. I'll give NWS props for that. Just say what is going to happen and when. If you're expecting the strongest winds near canyons, then "strong east winds near canyons" will suffice. Simon Pegg and Nick Frost need to give the undead "canyon winds" term a good whack in the head!

      Sometimes there is no easy explanation, and in trying to provide one, scientists and non-scientists alike can end up simplifying things to the point where they are completely wrong. There certainly are people out there watching the forecast who are curious about the underlying processes, but they are much better off spending a few minutes on Google Scholar than watching a TV infographic about high and low pressure systems having a turf war.

  2. During wind events like yesterday and December 2011, why does the Centerville–Farmington area get such high gusts compared to the rest of the Wasatch front?