A broad upper trough over the western United States initially brought snow to northeast Utah. As the trough deepened over the west, the main area of snowfall transitioned to southeast Utah as the flow aloft became southwesterly.
Every event with a place to put it; 4 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 GJT wrote it up.
A broad upper trough over the western United States initially brought snow to northeast Utah. As the trough deepened over the west, the main area of snowfall transitioned to southeast Utah as the flow aloft became southwesterly.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Feb 21, 4:07 AM MST, 3 hours 53 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
407 AM MST SAT FEB 21 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 407 AM MST SAT FEB 21 2015
AN ENERGETIC NORTHWEST FLOW IS IN THE PROCESS OF CARVING OUT A
LOW PRESSURE TROUGH OVER THE INTERMOUNTAIN WEST TODAY THROUGH
SUNDAY...WITH A LOW CLOSING OFF OVER THE DESERT SOUTHWEST ON
MONDAY. THE FIRST PHASE OF THIS LONG DURATION AND COMPLICATED
STORM BEGAN YESTERDAY OVER THE FORECAST AREA...AND WILL CONTINUE
TODAY AS ADDITIONAL DISTURBANCES EMBEDDED IN THE FLOW SWEEP OVER
THE FORECAST AREA FROM THE NORTHWEST. BY EARLY THIS EVENING AND
OVERNIGHT THE STORM WILL TRANSITION INTO ITS SECOND PHASE AS THE
FLOW BECOMES WESTERLY AS THE TROUGH ELONGATES INTO THE GREAT
BASIN. A SOUTHWEST FLOW WILL EVENTUALLY DEVELOP AS THE TROUGH
SLOWLY SHIFTS SOUTH THROUGH SUNDAY.
FOR TODAY...THE NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY NEAR
THE CONTINENTAL DIVIDE WILL BE FAVORED AS MOISTURE AND
DISTURBANCES DROP IN FROM THE NORTHWEST. ALSO THE NOSE OF A 110+KT
UPPER JET WILL MOVE JUST NORTH OF THE 4-CORNERS BY MIDDAY KEEPING
THE NORTHERN HALF OF THE CWA UNDER ITS FAVORABLE LEFT EXIT REGION.
THIS ALSO KEEPS THE CORE AND MORE UNSTABLE AREA OF THE TROUGH
BETTER POSITIONED FROM AROUND HIGHWAY 50 NORTHWARD. GRAUPEL IN
SALT LAKE EARLY THIS MORNING DEMONSTRATES THAT GOOD INSTABILITY IS
STILL UPSTREAM. SO EXPECT SHOWERS TO INCREASE LATE THIS MORNING
INTO EARLY THIS AFTERNOON...WHICH IS TIMED WELL FOR A DIURNAL
ASSIST. THE LOWER VALLEYS WILL STAY MOSTLY OUT OF IT TODAY...WITH
SOME CONVECTIVE SHOWERS POSSIBLE. BUT SNOW SHOWERS SHOULD SPREAD
INTO THE SAN JUANS THIS AFTERNOON AND INCREASE THIS EVENING.
THE NORTH WILL SEE A LULL TONIGHT AS THE STORM TRANSITIONS TO ITS
SECOND PHASE ON SUNDAY. GOOD ISENTROPIC LIFT DEVELOPS OVER
SOUTHEAST UT AND SOUTHWEST CO OVERNIGHT AND ESPECIALLY EARLY
SUN...AND SPREADS NORTHWARD BY MIDDAY. THIS WEST-SOUTHWEST FLOW
WILL PICK UP SOME BETTER MOISTURE AND WILL CARRY A DEEPER SURGE
OVER THE SOUTHERN SLOPES OF THE ABAJOS AND SAN JUANS...AND WILL
BRING THE POTENTIAL FOR HEAVY SNOW TO THOSE ZONES. IN ADDITION A
DEFORMATION ZONE WILL DEVELOP ACROSS THE FORECAST AREA WITH THE
HEAVIER SNOW GENERALLY ALONG...AND TO THE SOUTH OF THIS ZONE.
THROUGH THE DAY THIS DEFORMATION ZONE WILL SHIFT NORTHWARD AS THE
LOW CENTER SINKS SOUTH TOWARDS THE DESERT SOUTHWEST. THEREFORE
OTHER MOUNTAINS INCLUDING THE SOUTHERN SLOPES OF THE TAVAPUTS
PLATEAU AND THE FLATTOPS..AND SOUTHWARD WILL CONTINUE TO SEE GOOD
SNOWFALL ACCUMULATIONS ON SUNDAY. THEREFORE ADJUSTED THE
HIGHLIGHTS FOR THESE COLORADO MOUNTAINS...AND TO COVER THE ABAJO
AND LA SAL MOUNTAINS ABOVE 8000 FT WITH WINTER STORM WARNINGS
THROUGH MONDAY EVENING AT LEAST...AND BEYOND FOR THE SOUTHEAST UT
MOUNTAINS. (SEE THE LONG TERM DISCUSSION.)
FOR THE VALLEYS...THERE WILL BE THE POTENTIAL FOR GOOD
OVERRUNNING SNOWFALL ON SUNDAY. TEMPERATURES WILL HAVE COOLED
CONSIDERABLY DUE TO THE COLD ADVECTION IN THE FIRST PART OF THE
STORM...SO SNOW LEVELS WILL BE MUCH LOWER THAN WE HAVE SEEN FOR
QUITE SOME TIME. HOWEVER THE SOUTHERN VALLEYS REMAIN A WILD CARD
AS IT IS UNCERTAIN HOW MUCH COOLING THEY WILL SEE BY EARLY SUNDAY.
THEN THE WARMER SOUTHWEST FLOW MAY KEEP TEMPERATURES TOO WARM
THERE FOR ANY ACCUMULATIONS. WINTER STORM WATCHES ARE IN EFFECT
FOR A FEW OF HIGHER WEST-CENTRAL COLORADO VALLEYS. WILL LEAVE
THESE FOR NOW...AND WILL NOT ADD OTHER VALLEYS AT THIS TIME AS
TEMPERATURES...SNOW LEVELS AND SNOW AMOUNTS REMAIN TRICKY FOR THE
LOWER CENTRAL AND SOUTHERN VALLEYS. THE PORTION OF THE FORECAST
AREA NORTH OF THE TAVAPUTS AND FLATTOPS ARE NOT FAVORED FOR THIS
TYPE OF FLOW ON SUNDAY AS THE DEFORMATION ZONE WILL REMAIN WELL TO
THE SOUTH. HOWEVER AT TIMES SCATTERED SHOWERS WILL BE POSSIBLE AS
SOME INSTABILITY PERSISTS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 407 AM MST SAT FEB 21 2015
THE SECOND ACT OF OUR LATEST STORM CONTINUES SUNDAY NIGHT THROUGH
MONDAY EVENING AS FLOW ALOFT BECOMES INCREASINGLY DIFFLUENT OVER
THE REGION WITH STRONG ISENTROPIC UPGLIDE OVER THE STALLED FRONT.
CONCURRENTLY...DECENT DIVERGENCE SUPPLIED BY LEFT EXIT REGION OF
CYCLONICALLY CURVED JET WORKS IN CONCERT WITH OROGRAPHIC LIFT
SUPPLIED BY FAIRLY VIGOROUS SOUTHWEST FLOW AT 700 MB TO PROVIDE
NECESSARY LIFT FOR PRECIPITATION. FINALLY...MOIST AIRMASS PUMPED
OVER THE AREA FROM THE SOUTHWEST WITH SPECIFIC HUMIDITY HOVERING
NEAR 3.5 G/KG APPEARS SUFFICIENT FOR SIGNIFICANT SNOWFALL ACROSS
THE SOUTHERN MOUNTAINS AND VALLEYS THROUGH MIDNIGHT MONDAY NIGHT.
MODELS IN GOOD AGREEMENT...SO FELT COMFORTABLE UPGRADING WATCHES
IN THE MOUNTAINS TO WARNINGS WITH ACCUMULATIONS OF UP TO 2 FEET
LIKELY. THE VALLEYS LESS CERTAIN AND HEAVY SNOW NOT EXPECTED UNTIL
SUNDAY AFTERNOON SO CONTINUED WATCHES IN THE I-70 CORRIDOR EAST
OF PALISADE AND IN THE GUNNISON BASIN. GRAND VALLEY NEEDS TO BE
WATCHED AS NAM POINTS TO POTENTIAL FOR 3 TO 6 INCH ACCUMULATIONS.
HOWEVER...VALLEY BOTTOM WILL BE FLIRTING WITH THE RAIN SNOW LINE
AND SURFACE TEMPERATURE RELATIVELY WARM...BOTH OF WHICH COULD LIMIT
ACCUMULATION. FOUR CORNERS REGION ALSO BEARS CLOSE MONITORING.
SNOW LEVEL EVEN HIGHER TO THE SOUTH SO SIMILAR FACTORS WORKING
AGAINST SNOW ACCUMULATIONS. EXCEPTION MAY BE PAGOSA SPRINGS WHICH
IS SIGNIFICANTLY HIGHER THAN EITHER DURANGO OR CORTEZ.
HIGHLIGHTS MAY NEED TO BE EXTENDED ACROSS THE SAN JUAN MOUNTAINS
MONDAY NIGHT AS THE 7H LOW CENTER SLIDES ALONG THE CO/NM BORDER
DURING THE NIGHT KEEPING SNOW GOING. THE LOW IS THEN FORCED SOUTH
ON TUESDAY AS ANOTHER DISTURBANCE BEGINS TO MOVE SOUTHEASTWARD
ACROSS THE PACIFIC NORTHWEST PROVIDING THE PUSH NEEDED TO MOVE
IT ALONG. AS SUCH...THE REGION WILL EXPERIENCE RELATIVELY QUIET
WEATHER TUESDAY AND TUESDAY NIGHT...EXCEPT FOR ACROSS THE CENTRAL
SAN JUAN MOUNTAINS WHERE SCATTERED SNOW SHOWERS ARE EXPECTED TO
LINGER FOR A TIME.
DETAILS DIFFER...BUT MODELS INDICATED THAT UNSETTLED CONDITIONS
REDEVELOP WEDNESDAY AND WILL CONTINUE OFF AND ON THROUGH THE
REMAINDER OF THE COMING WORK WEEK. TEMPERATURES WILL BEGIN THE
WEEK COLDER THAN NORMAL BEFORE CLIMBING TO NEAR NORMAL AT MIDWEEK
AS THE AREA FINDS ITSELF IN A LULL AHEAD OF THE NEXT STORM.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 407 AM MST SAT FEB 21 2015
SNOW AND SNOW SHOWERS WILL DEGRADE FLIGHT CONDITIONS ACROSS THE
WESTERN AND CENTRAL COLORADO MOUNTAINS FOR PROLONGED PERIODS
THROUGH 12Z SUNDAY AS A STRONG WINTER STORM CONTINUES TO IMPACT
THE AREA. KHDN...KSBS...KASE AND KEGE WILL LIKELY BE IN AND OUT OF
SNOW AND/OR SNOW SHOWERS DURING THIS PERIOD. OTHERWISE...VFR WILL
PREVAIL AT THE LOWER VALLEY TAF SITES ACROSS EASTERN UTAH AND
SOUTHWEST COLORADO. EXPECT GUSTY WINDS AT TIMES...ESPECIALLY IN
PROXIMITY TO SHOWERS. THE BULK OF THE PRECIPITATION WILL REMAIN
NORTH OF HIGHWAY 50 THIS MORNING. HOWEVER...SCATTERED SNOW SHOWERS
ARE POSSIBLE IN THE SAN JUANS THIS MORNING...THEN INCREASE IN
COVERAGE AND INTENSITY THIS AFTERNOON. MODERATE TO HEAVY SNOW
WILL CONTINUE ALONG AND SOUTH OF THE I-70 CORRIDOR TONIGHT WITH
FLIGHT CATEGORIES VERY LIKELY TO BE DEGRADED IN SNOW...OR A RAIN
SNOW MIX.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 AM MST SUNDAY FOR COZ002-005-008.
WINTER STORM WARNING UNTIL MIDNIGHT MST MONDAY NIGHT FOR COZ003-
009-010-012-013.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR COZ014.
WINTER STORM WARNING FROM 6 AM SUNDAY TO MIDNIGHT MST MONDAY
NIGHT FOR COZ017>019.
WINTER STORM WARNING UNTIL 6 AM MST SUNDAY FOR COZ004.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR COZ007-008.
UT...WINTER WEATHER ADVISORY UNTIL 6 AM MST SUNDAY FOR UTZ023.
WINTER STORM WARNING FROM 6 AM SUNDAY TO 6 AM MST TUESDAY FOR
UTZ028.
&&
SHORT TERM...EH
LONG TERM...NL
AVIATION...TGJTThe national radar mosaic for the moment the first event began.
2 winter weather, 2 winter storm. Local standard time, as filed.
Snowfall amounts of 6 to 8 inches were measured above the 8000 foot level.
Snowfall amounts of 10 to 18 inches were measured across the area. Locally higher amounts included 22 inches at the Camp Jackson SNOTEL site. Wind gusts of 20 to 40 mph resulted in areas of blowing and drifting snow.
Snowfall amounts of 3 to 6 inches were measured across the area.
Measured snowfall amounts of 11 to 16 inches were reported from the official cooperative observation stations. However, heavier amounts up to 2 and 3 feet deep were reported on Navajo Nation lands in San Juan County, with drifts waist-high in some locations. This situation made local roads impassable and caused many families to be snowed in, which at one point was estimated to be up to 350 families. The Navajo Nation’s Emergency Operations Center (EOC) was activated, and the Navajo chapters in southeast Utah declared a State of Emergency. Schools in the Bluff and Montezuma Creek areas were closed until March 2 and 3rd, respectively, while schools in the Monument Valley area were closed through early March. Multiple power outages were reported, cell phone towers were inoperable, and many trees were damaged or uprooted.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2015Every state in 2015This day in weather historyWarnings in Utah, February 2015
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: 555814, 555813, 555816, 555815.