The active weather pattern continued into late March, with yet another winter storm bringing snowfall to portions of Utah.
Every event with a place to put it; 7 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SLC wrote it up.
The active weather pattern continued into late March, with yet another winter storm bringing snowfall to portions of Utah.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Salt Lake City, UT wrote its last area forecast discussion before the first event at Mar 21, 2:56 AM MST, 3 hours 4 minutes earlier.
Area Forecast Discussion
National Weather Service Salt Lake City UT
356 AM MDT Tue Mar 21 2023
.SYNOPSIS...A moist Pacific storm system will bring significant
snow to the mountains and some mountain valleys of Utah through
Wednesday night. Unsettled weather will continue Thursday before a
rather unseasonably cold system moves through the area on Friday.
Yet another system will follow late Saturday into Sunday.
&&
.SHORT TERM (Through 12Z Thursday)...Seeing a relative lull in
precipitation across Utah and southwest Wyoming this morning with
our first trough having exited and the second moving onshore along
the California coast. This second system is tapping into
tropical moisture which is already advecting into southern Utah in
southerly flow. As a result, some light precipitation has already
developed, and this will continue to become more widespread
through the morning. As the center of the California low pivots
this afternoon, the deep moisture will spread northward across the
remainder of the forecast area, allowing coverage of precipitation
to increase. Precip will stay widespread over southern Utah
Tuesday night through Wednesday morning with the heaviest
precipitation anticipated for northern Utah during this time as a
series of ejecting shortwaves and then the front edge of the
trough and then the associated cold front move through. Latest
guidance remains fairly consistent with regard to anticipated
snow totals, which will be quite high across some of the higher
terrain of southern Utah, with significant totals also anticipated
for the remainder of the mountains as well as the Wasatch Back and
Uinta Basin. Made no changes to headlines with this package.
During this period guidance also indicates a strong pressure
gradient, particularly over western and southern Utah with many
areas of 700mb flow in excess of 50 knots, particularly overnight
for western Utah. Inspection of ensemble guidance shows the
majority of members putting max gusts over spots in southern and
western Utah not currently covered by a Winter Storm Warning in
the 40 to 45mph range, and would expect this given the moist
airmass and the overnight timing of the strongest flow. As these
types of gusts would be marginal for a Wind Advisory, will hold
off on any headlines at this time and allow the day shift to take
another look.
As the trough heads out of the area Wednesday evening, associated
precipitation is expected to diminish from south to north.
However, lingering moisture and shortwave energy should keep at
least some showers going over the mountains of northern Utah
through Thursday morning.
.LONG TERM (After 12Z Thursday)...It may be the second day of
spring, but the long-term period looks more like winter. Active
weather continues with chances of precipitation through Day 7 and
temperatures 20-25 degrees below normal over the weekend.
The overall pattern for Thu-Sat involves the exiting trough to our
east and an incoming feature that might be best described as a broad
closed low approaching our area by Sunday. A shortwave trough
crossing northern Utah on Friday will produce precipitation across
much of northern and central Utah and southwest Wyoming, with still
10-40% chances across southern Utah. There is still some uncertainty
with how far south this shortwave reaches, with 45% of ensemble
members favoring QPF across the entire area, whereas the other 55%
greatly favor northern Utah. Chances for precipitation continue on
Saturday despite less impressive dynamics.
The most impressive aspect of the approaching closed low is the cold
temperatures it is expected to bring starting Friday. H7
temperatures will likely bottom out on Saturday at -15C to -18C
across the north (25th-75th ensemble spread). For reference, the
daily minimum H7 temperatures for Mar 25 is -15C at KSLC. This
translates to surface highs and lows at 20-25 degrees below normal
across the entire forecast area. Lows in the single digits are
possible across various higher elevation valleys (i.e. Wasatch Back,
Bear River Valley, etc) beginning Friday night.
As you then might expect, all valleys except the St George metro and
areas near Lake Powell will (95% likelihood) see snow this weekend.
But first, most valleys will likely see rain on Thursday afternoon
before changing to a snow precipitation type Thursday late evening,
which will continue through the weekend. Despite increasing
confidence in snowfall, valley accumulations are likely to remain
under 6", with only an 11% likelihood of exceeding 4" at KSLC.
The closed low feature will reach our area by Sunday, further
continuing precipitation chances across the area (does this sound
like a broken record yet?). Uncertainty increases at this time,
however. Ensemble members agree that the pattern will stay active,
but exact details on features are unclear. Members are at least
hinting at a brief break in precipitation on Monday, but with
another trough possibly developing upstream, this would be short-
lived.
&&
.AVIATION...KSLC...Scattered rain showers will push north starting
around 21-22z, likely continuing for the valid TAF period. With
onset of scattered showers, CIGs near 5000ft AGL are likely, with
occasional breaks possible. MVFR conditions are possible (35%
likelihood), mainly after ~05z. Southerly winds will prevail, with
increasing flow after ~10z Wednesday.
.REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers will
continue to push northward across the area. Currently (~10z), the
leading edge is across KCDC-KBCE. Showers will reach KMLF around 14-
15z, KPVU around 19-20z, and KLGU around 00-01z. Showers will
increase in coverage, especially across southern Utah. Within
showers, MVFR to IFR conditions are possible, especially across
southern Utah and higher elevations where snow is possible. Early
this morning, MVFR to IFR CIGs are likely to continue across higher
elevation sites. Overall southerly flow is likely to prevail across
much of the area. There is a 15% chance of thunder across far
southwestern Utah, including KSGU (00-09z).
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory from 6 PM this evening to 6 AM MDT
Thursday for UTZ108-110.
Winter Storm Warning from 3 PM this afternoon to 6 AM MDT
Thursday for UTZ111>113.
Winter Weather Advisory from 3 PM this afternoon to 6 PM MDT
Wednesday for UTZ114-117.
Winter Storm Warning until 6 AM MDT Thursday for UTZ124-125-127-
128.
WY...None.
&&
SHORT TERM...Traphagan
LONG TERM/AVIATION...Cunningham
For more information from NOAA's National Weather Service visit...
http://weather.gov/saltlakecityThe national radar mosaic for the moment the first event began.
5 heavy snow, 2 winter weather. Local standard time, as filed.
Several SNOTEL stations including Little Grassy, Lonesome Beaver, and Big Flat recorded 1.5 to 2.9 inches of snow water equivalent, resulting in approximately 18 to 36 inches of snow.
The Agua Canyon SNOTEL site recorded 2.4 inches of snow water equivalent, resulting in approximately 30 inches of snow.
Several SNOTEL stations including Clear Creek #2, Timberline, and Mammoth-Cottonwood recorded 1.0 to 1.4 inches of snow water equivalent, resulting in approximately 12 to 18 inches of snow.
A two-vehicle crash occurred just before 7PM MDT on U.S. Highway 89, and resulted in 3 fatalities. The Utah Department of Transportation reported that it was snowing at the time of the accident and the road was snow-covered. The Utah Highway Patrol indicated that weather was a likely factor in the crash. Though surface observations in this area are sparse, a nearby RAWS site reported 33 degrees near the time of the crash, with ongoing precipitation.
Several SNOTEL stations including Parrish Creek, Farmington, and Ben Lomond Peak recorded 1.7 to 2.8 inches of snow water equivalent, resulting in approximately 20 to 34 inches of snow.
Several SNOTEL stations including Brighton, Atwater, and Snowbird recorded 1.7 to 2.1 inches of snow water equivalent, resulting in approximately 21 to 26 inches of snow.
Snow Squall. The US-6 @ Eureka mesonet station recorded a period of wind gusts from 51 to 70 mph and visibility between approximately 0.12 to 0.37 miles with moderate to heavy precip reported (snow) as a snow squall moved through the area.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Winter Weather, South Central Utah | 2023-03-21 | 46 | Female | Vehicle/Towed Trailer | Indirect |
| Winter Weather, South Central Utah | 2023-03-21 | 64 | Female | Vehicle/Towed Trailer | Indirect |
| Winter Weather, South Central Utah | 2023-03-21 | 16 | Male | Vehicle/Towed Trailer | Indirect |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2023Every state in 2023This day in weather historyWarnings in Utah, March 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1088567, 1088568, 1088566, 1088869, 1088564, 1088565, 1088569.