A broad upper trough moved over the region late on the last day of February through the first day of March. The upper trough was followed by a moist northwest flow on March 2nd which persisted into March 3rd.
Every event with a place to put it; 3 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 moved over the region late on the last day of February through the first day of March. The upper trough was followed by a moist northwest flow on March 2nd which persisted into March 3rd.
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 29, 9:52 AM MST, 3 hours 8 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
952 AM MST WED FEB 29 2012
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 442 AM MST WED FEB 29 2012
ONE STORM IS WINDING DOWN THIS MORNING ACROSS OUR CWA WHILE THE NEXT
STORM IS RAMPING UP ACROSS THE PACIFIC NORTHWEST. A FEW FLURRIES OR
LIGHT SNOW SHOWERS POPPING UP IN THE WAA REGIME OVER WESTERN
COLORADO AS THE TRANSITORY RIDGE MOVES THROUGH THIS MORNING. GOES
DERIVES SATELLITE PRODUCTS SHOWING A MODEST MOISTURE SOURCE
AVAILABLE FOR THE NEXT STORM WITH HIGH CLOUDS ALREADY INVADING
EASTERN UTAH AND THE COLORADO BORDER. MOISTURE TRANSPORT VECTS SHOW
THIS UPPER LEVEL MOISTURE ARRIVING AROUND THE 305K SURFACE
WHILE...THE LOWER SURFACES SHOW THE BETTER MOISTURE ARRIVING LATE
THIS AFTERNOON INTO THIS EVENING...WITH MIXING RATIOS ONCE AGAIN
REACHING ABOVE 2 G/KG. WHILE THIS SYSTEM MAY BE LACKING IN A
STRONGER MOISTURE SOURCE THE COLDER NATURE OF THE STORM SHOULD
PRODUCE AN EFFICIENTLY DEEP DENDRITIC LAYER NEAR MOUNTAIN TOP LEVEL
AND SHOULD HELP PRODUCE INFLATED SNOW TO LIQUID RATIOS. LARGE SCALE
ASCENT WILL GRADUALLY INCREASE THROUGH THE DAY LEADING TO SATURATION
FROM THE TOP DOWN. AS THIS MOISTURE MIXES WITH AN INCREASING W/SW
OROGRAPHIC FLOW EXPECT SNOW SHOWERS TO BECOME MORE WIDESPREAD ACROSS
THE NORTHERN AND CENTRAL MOUNTAINS BY MID EVENING. THOUGH
ACCUMULATIONS WILL BE ON THE LIGHT SIDE DECIDED TO HOIST WINTER
STORM WARNINGS BEGINNING THIS EVENING. LIFT WILL BE DEFINITELY BE
ENHANCED DURING THE EARLY MORNING BY THE UPPER JET SAGGING SOUTHWARD
THROUGH THE CWA. MODELS ARE HINTING AT A WEAK MID LEVEL FRONTO BAND
CONNECTING THIS UPPER DIVERGENCE WITH LOW LEVEL CONVERGENCE FROM A
SURFACE FRONT DIPPING INTO THE NORTHERN ZONES. THUS DECIDED TO ALSO
PLACE SOME OF THE LOWER ELEVATIONS INTO A WINTER WEATHER ADVISORY AS
THERE SHOULD BE A BETTER BURST OF SNOW AS THIS FRONT PASSES TO JUST
NORTH OF I-70 BY SUNRISE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 442 AM MST WED FEB 29 2012
MOIST WESTERLY FLOW WILL CONTINUE TO BRING WIDESPREAD SNOW TO THE
MOUNTAINS THURSDAY. FAIRLY STEEP LAPSE RATES WILL BE IN PLACE AS
COLDER AIR ALOFT MOVES IN JUST AHEAD OF APPROACHING LONG WAVE
TROUGH. THIS INCREASING INSTABILITY MAY LEAD TO A FEW
THUNDERSTORMS BY LATE IN THE DAY...WITH CONVECTION PLAYING A BIG
ROLE IN SNOWFALL AMOUNTS. HARD TO PINPOINT SPECIFIC AREAS AT THIS
TIME...BUT MOISTURE WILL BE SUFFICIENT WITH SPECIFIC HUMIDITIES
CLIMBING INTO THE 3 TO 4 G/KG RANGE. OROGRAPHICS WILL ALSO BE
PLAYING A ROLE...ALTHOUGH SPEEDS NOT AS IMPRESSIVE AS PREVIOUS
SYSTEM. FINAL POSITIVE WITH THIS EVENT WILL BE TEMPS ALOFT
HOVERING WITHIN THE DENDRITIC GROWTH ZONES...SO SHOULD SEE SOME
EFFICIENT SNOW PRODUCTION THROUGHOUT THE REGION.
THE HEAVIER SNOW WILL SPREAD SOUTH THURSDAY AFTERNOON THROUGH
FRIDAY AS A WEAK SFC FRONT SAGS SOUTH AND ANOTHER PIECE OF ENERGY
SPINS UP ON THE BACK SIDE OF THE TROUGH. THIS TIGHT LITTLE AREA OF
ENERGY WILL IMPACT OUR SOUTHERN ZONES...BRINGING HEAVY SNOW TO THE
SOUTHERN MOUNTAINS THROUGH FRIDAY. MAY ALSO SEE A PERIOD OF
ENHANCED PRECIPITATION INTO THE SOUTHERN VALLEYS THURSDAY NIGHT
AND WILL NEED TO WATCH THIS POTENTIAL OVER THE NEXT FEW SHIFTS.
FOR NOW...HAVE HOISTED A WINTER STORM WATCH FOR THE SOUTHERN
MOUNTAINS STARTING EARLY THURSDAY THROUGH LATE FRIDAY AFTERNOON.
WARNINGS AND ADVISORIES WILL BE IN PLACE FOR THE NORTHERN AND
CENTRAL MOUNTAINS AND VALLEYS BEGINNING THIS EVENING AND
CONTINUING THROUGH EARLY FRIDAY MORNING.
SNOWFALL AMOUNTS WILL VARY GREATLY DUE TO THE CONVECTIVE
ELEMENT...BUT AMOUNTS STILL EXPECTED TO EXCEED WARNING CRITERIA OVER
A LARGE ENOUGH AREA TO JUSTIFY THE WARNINGS. THINGS DRY OUT FRIDAY
NIGHT AND SATURDAY FROM WEST TO EAST WITH FLAT RIDGING
TRANSITIONING INTO DRY WEST TO SOUTHWEST FLOW BY SUNDAY. NEXT
PRECIPITATION MAKER ARRIVES BY MIDWEEK...WITH ANOTHER ROUND OF
WIDESPREAD MOUNTAIN SNOW POSSIBLE. STILL SEVERAL DAYS AWAY AND
TIMING WILL BE AN ISSUE.
TEMPERATURES EXPECTED TO RUN ON THE COOL SIDE OF NORMAL THROUGH
FRIDAY...BEFORE CLIMBING BACK TO SEASONAL NORMS OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 943 AM MST WED FEB 29 2012
MID AND UPPER LEVEL CLOUDS WILL CONTINUE TO INCREASE ACROSS
WESTERN COLORADO AND EASTERN UTAH THIS AFTERNOON. ACROSS THE NRN
MTNS THIS MAY PRODUCE AREAS OF MOUNTAIN OBSCURATION. OTHERWISE ALL
TAF SITES SHOULD REMAIN VFR. THE NEXT SYSTEM WILL ARRIVE TO THE
REGION OVERNIGHT AND BRING DETERIORATING CONDITIONS TO THE CENTRAL
AND NORTHERN MOUNTAINS BY MID EVENING...SPREADING TO THE LOWER
VALLEYS THROUGH THE NIGHT. MOUNTAIN OBSCURATIONS WILL BECOME MORE
WIDESPREAD AND THE KCAG...KHDN...KASE AND KEGE TERMINALS ARE
LIKELY TO SEE WIDESPREAD MVFR WITH PERIODS OF IFR CONDITIONS
THROUGH THURSDAY MORNING. SNOW SHOWERS WILL BE IN THE VICINITY OF THE
OTHER LOWER VALLEY TERMINALS...BUT CONFIDENCE STILL REMAINS TOO
LOW TO PLACE THEM BELOW VFR CATEGORIES ATTM.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 9 AM MST
FRIDAY FOR COZ002-003-005-008.
WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY
AFTERNOON FOR COZ017>019.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 9 AM MST FRIDAY
FOR COZ004-009-010-012-013.
UT...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 9 AM MST
FRIDAY FOR UTZ023-025.
WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY
AFTERNOON FOR UTZ028.
&&
SHORT TERM...15
LONG TERM....JDC
AVIATION...MCHAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 559 AM MST WED FEB 29 2012 COZ001>014-017>023-UTZ022>025-027>029-011300- LOWER YAMPA RIVER BASIN-CENTRAL YAMPA RIVER BASIN- ROAN AND TAVAPUTS PLATEAUS-ELKHEAD AND PARK MOUNTAINS- UPPER YAMPA RIVER BASIN-GRAND VALLEY-DEBEQUE TO SILT CORRIDOR- CENTRAL COLORADO RIVER BASIN-GRAND AND BATTLEMENT MESAS- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAIN VALLEYS- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- WEST ELK AND SAWATCH MOUNTAINS-FLATTOPS- UPPER GUNNISON RIVER VALLEY-UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE- NORTHWEST SAN JUAN MOUNTAINS-SOUTHWEST SAN JUAN MOUNTAINS- PARADOX VALLEY/LOWER DOLORES RIVER- FOUR CORNERS/UPPER DOLORES RIVER-ANIMAS RIVER BASIN- SAN JUAN RIVER BASIN-SOUTHEAST UTAH-EASTERN UINTA MOUNTAINS- EASTERN UINTA BASIN-TAVAPUTS PLATEAU-ARCHES/GRAND FLAT- LA SAL AND ABAJO MOUNTAINS-CANYONLANDS/NATURAL BRIDGES- 559 AM MST WED FEB 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED SNOW SHOWERS TODAY WILL BECOME MORE NUMEROUS AND INCREASE IN COVERAGE TONIGHT AS ANOTHER STRONG PACIFIC STORM MOVES INTO THE REGION. PERIODS OF SNOW...HEAVY AT TIMES...WILL OCCUR OVER THE MOUNTAINS AFTER MIDNIGHT AND CONTINUE THROUGH THURSDAY. NUMEROUS WINTER STORM WARNINGS...ADVISORIES AND WATCHES ARE IN EFFECT TONIGHT THROUGH FRIDAY. FOR MORE DETAILS ON THIS LATEST WINTER STORM...GO TO WWW.WEATHER.GOV/GJT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SNOW WILL CONTINUE OVER THE MOUNTAINS...WITH SCATTERED SNOW SHOWERS OVER THE VALLEYS THURSDAY AND FRIDAY. THE SNOW ENDS LATE FRIDAY AFTERNOON...WITH DRY AND WARMER CONDITIONS THEN SETTLING OVER THE AREA THROUGH EARLY NEXT WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT...HOWEVER SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS TO THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
758 AM MST WED FEB 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0744 AM SNOW 7 N BAYFIELD 37.34N 107.59W
02/29/2012 M10.1 INCH LA PLATA CO TRAINED SPOTTER
STORM TOTAL SNOW FALL... WITH WATER EQUIVALENT-STORM
TOTAL OF 0.69 INCHES... BLOWING SNOW IN STRONG WINDS
&&
EVENT NUMBER GJT1200233
BKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
815 AM MST WED FEB 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0801 AM SNOW 12 ENE COLUMBINE PASS 38.46N 108.16W
02/29/2012 M8.0 INCH MONTROSE CO TRAINED SPOTTER
24 HOUR SNOWFALL WITH WATER EQUIVALENT 0.80
INCHES-STORM TOTALS 15 INCHES SNOWFALL WITH 1.55 INCHES
WATER EQUIVALENT... SNOW DRIFTS UP TO 2 FEET TALL IN
STRONG WINDS
&&
EVENT NUMBER GJT1200234
BKThe national radar mosaic for the moment the first event began.
3 winter storm. Local standard time, as filed.
This storm began to impact the area with heavy snowfall on the last day of February. Please see the March Storm Data Report for a summary for this event.
This storm began to impact the area with heavy snowfall late on the last day of February. Please see the March Storm Data Report for a summary for this event.
This storm began to impact the area with heavy snowfall late on the last day of February. Please see the March Storm Data Report for a summary for this event.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2012Every state in 2012This day in weather historyWarnings in Colorado, February 2012
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: 370540, 370975, 370974.