Tuesday, December 30, 2014

A Blustery Day

source: KSL.com
The large scale, or synoptic, weather conditions have set up another downslope wind storm for northern Utah. If you live north of Salt Lake City you're pretty familiar with these types of wind storms. These events cause freeway closures, blow over trampolines, and carry your trampoline down the block. These storms occur when a mass of cold air comes into Utah from Wyoming and "waterfalls" down the Wasatch Mountains causing a cold, strong wind. If you live in Utah county you can thank the Uintah mountains for the lighter winds.

Still, winds in Spanish Fork are stronger today than normal on this downslope windstorm type of day. The ten minute averaged winds are around 15 mph and gusts nearing 30 mph.

However, winds are much stronger further north. At the University of Utah, on top of the William Browning Building, ten minute average wind speeds are 25 mph with stronger winds at the mouth of Red Butte Canyon. Gusts are over 55 mph.
And the temperature  just keeps dropping, currently 10 degrees F. That's a cold wind. The wind chill makes it feel like -12 degrees F.

And a little further north, in Farmington, some of the strongest winds have been reported. This station currently is reporting sustained winds of 44 mph with gusts up to 77 mph! Surrounding stations measure similar wind speeds and gusts.
 I remember being told that Lagoon's ferris wheel, the Sky Ride, was built to withstand a hurricane. We don't have hurricanes in Utah (obviously), but we definitely get hurricane strength winds.

Clearfield Traffic Camera with blowing snow.
source: UDOT.utah.gov
source: KSL.com
I-15 is closed to semis due to the high winds and tipped trailers. 



These high winds will last most of the day and into the night. By this evening you may have new snow to shovel while you're neighbor will be lucky enough to have no more snow in their yard. It all depends on where those snow drifts settle.

From the National Weather Service:

High Wind Warning

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
202 AM MST TUE DEC 30 2014

UTZ002-302300-
/O.CON.KSLC.HW.W.0011.000000T0000Z-141231T1100Z/
NORTHERN WASATCH FRONT-
INCLUDING THE CITIES OF...BRIGHAM CITY...OGDEN...BOUNTIFUL
202 AM MST TUE DEC 30 2014

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 4 AM MST WEDNESDAY...

* AFFECTED AREA...THE NORTHERN WASATCH FRONT FROM BRIGHAM CITY
  SOUTHWARD TO NORTH SALT LAKE. THE STRONGEST WINDS ARE OCCURRING
  BETWEEN LAYTON AND BOUNTIFUL...INCLUDING FARMINGTON AND
  CENTERVILLE.

* WINDS...EAST WINDS GUSTING IN EXCESS OF 60 MPH...WITH LOCAL
  GUSTS IN EXCESS OF 75 MPH.

* TIMING...THE STRONGEST WINDS ARE FORECAST TO OCCUR THIS
  MORNING...PEAKING MID TO LATE MORNING...BEFORE GRADUALLY
  DIMINISHING THROUGH TONIGHT.

* IMPACTS...THIS IS A POTENTIALLY DANGEROUS SITUATION. STRONG
  CROSSWINDS ARE OCCURRING ALONG I-15...HIGHWAY 89 AND THE LEGACY
  PARKWAY THROUGH DAVIS AND WEBER COUNTIES WHICH WILL CREATE
  HAZARDOUS TRAVEL FOR HIGH PROFILE VEHICLES AND THOSE WITH
  TRAILERS. SIGNIFICANT BLOWING AND DRIFTING OF SNOW WILL ALSO
  CAUSE GREATLY REDUCED VISIBILITY AND SLICK ROADWAYS. VERY COLD
  WIND CHILLS CAN ALSO BE EXPECTED...WITH READINGS OF 20 TO 25
  DEGREES BELOW ZERO. POWER OUTAGES ARE POSSIBLE... GIVEN THE VERY
  COLD TEMPERATURES HAVE A CONTINGENCY PLAN IN THE EVENT OF A LOSS
  OF HEAT. LOOSE OBJECTS SUCH AS TRASH CANS... TRAMPOLINES AND
  LAWN ORNAMENTS WILL BECOME AIRBORNE RESULTING IN POTENTIAL
  PROPERTY DAMAGE. WIND SENSITIVE OPERATIONS WILL BE AFFECTED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED
OR IS OCCURRING. SUSTAINED WIND SPEEDS OF AT LEAST 40 MPH OR
GUSTS OF 58 MPH OR MORE CAN LEAD TO PROPERTY DAMAGE. VEHICLES...
ESPECIALLY HIGH PROFILE VEHICLES...CAN BE DIFFICULT TO CONTROL AT
TIMES IN HIGH WINDS. MOTORISTS SHOULD TAKE EXTRA CAUTION...
ESPECIALLY WHILE CROSSING BRIDGES...OVERPASSES AND UNSHELTERED
AREAS.

Also be aware of the elevated avalanche danger today:
THIS AVALANCHE WARNING IS FOR CANYON MOUTHS AND FOOTHILLS OF
CACHE...DAVIS...WEBER AND EASTERN SALT LAKE COUNTIES. STRONG WIND
WILL CREATE POTENTIALLY DANGEROUS WIND SLAB AVALANCHE CONDITIONS
IN LOW ELEVATION AREAS WHERE PEOPLE DO NOT NORMALLY SEE
AVALANCHES. AVALANCHE DANGER IS EXPECTED TO INCREASE TODAY AND
CONTINUE INTO WEDNESDAY.

THIS WARNING DOES NOT INCLUDE SKI AREAS OR HIGHWAYS WHERE
AVALANCHE CONTROL IS NORMALLY DONE.

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