Strong and persistent temperature inversions over snow-covered ground caused dense fog to form in low valley locations.
Every event with a place to put it; 2 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.
Strong and persistent temperature inversions over snow-covered ground caused dense fog to form in low valley locations.
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 4, 2:58 AM MST, 4 hours 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 258 AM MST THU FEB 4 2010 .SHORT TERM...TODAY THROUGH FRIDAY NIGHT UNDER MOSTLY CLEAR SKIES TEMPS PLUMMETED TO THE SINGLE DIGITS OVER EAST CNTRL UTAH AND NOT SURPRISINGLY FOG REFORMED. ELSEWHERE LIKE THE UINTA VALLEY AND THE GRAND VALLEY SOME CLD COVER EARLY MODERATED TEMPS AND FOG HAS BEEN SLOW TO REDEVELOP...BUT SHOULD BE WATCHED. OFF AND ON SNOW SHOWERS HAVE ALSO BEEN REPORTED IN THE CEZ...DRO...PSO AREA. SRN BRANCH OF SPLIT FLOW TROF PASSES OVER THE CWA THIS MORNING AND THE NRN BRANCH PASSES THIS AFTERNOON. BEST FORCING SEEMS TO OCCUR WITH SFC FRONTAL BAND PROGGED TO SLIDE THRU GJT EARLY THIS MORNING. THEN COLD ADVECTION AND RESULTING STEEP LAPSE RATES KEEP CONVECTIVE SHOWERS GOING OVER THE MTNS THROUGH THE DAY. HEAVIEST PCPN EXPECTED OVER THE NRN MTNS WHERE 2-4 INCHES CAN BE EXPECTED OVER THE PARK AND NRN GORE RANGES AS MT TOP TEMPS SUPPORT GOOD DENDRITIC GROWTH. HIGH PRESSURE BEGINS TO BUILD OVER THE GRT BASIN TONIGHT THEN SLOWLY TRANSLATE EWRD AHEAD OF THE NEXT PACIFIC WEATHER SYSTEM. THIS BRINGS DRY WX LATE TONIGHT AND EARLY FRIDAY...BUT AS RIDGE AXIS PASSES FRI AFTERNOON WARM ADVECTION/OMEGA DRIVEN PCPN BEGINS TO BREAK OUT OVER THE MTNS OF ERN UTAH AND WRN CO...INCREASING FRIDAY NIGHT. TEMPS STILL REMAIN PROBLEMATIC...BUT EXPECT WARMER TEMPS TODAY AS SFC FRONT SHOULD BREAK OUT MOST VALLEY INVERSIONS. .LONG TERM...SATURDAY THROUGH WEDNESDAY NIGHT... BEGINNING OF LONG-TERM BRINGS PRECIP TO ERN UT AND WRN CO AS RIDGE BREAKS DOWN AHEAD OF TROF. THIS PRECIP WILL OVERSPREAD REMAINDER OF CWA BY SAT EVENING AS FLOW BECOMES MORE ZONAL AND TROF CONTINUES EWRD MOVEMENT. AS THIS OCCURS...ALL MODELS HIGHLIGHT RETROGRADING SHORTWAVE DROPPING SWRD FROM CA/US BORDER. AS IT APPROACHES IT WILL BECOME SHEARED AS PARENT LOW OVER CANADA WILL DEEPEN SOMEWHAT AS SHEAR ZONE ROTATES AROUND LOW. THIS COMBINATION OF EVENTS WILL CAUSE PROLONGED PERIOD OF PRECIP THAT MAY PERSIST THRU TUE NIGHT/EARLY WED MORNING. WITH FIRST TROF...MOST PRECIP APPEARS TO BE OVER SAN JUANS/ABAJOS/LA SALS...WHILE SECOND SYSTEM WILL AFFECT CONTINENTAL DIVIDE. INCD POPS/QPF/SNOW AMTS IN RESPONSE BUT ONLY CONSERVATIVE AMTS FOR THE TIME BEING. WEEKEND WILL BEAR WATCHING AS HIGHLIGHTS A DISTINCT POSSIBILITY. OTHER CONCERN WILL BE TEMPS AS MOS GUIDANCE SHOWING A DROP OF CLOSE TO 12 DEG FOR HIGHS WITH LOWS DROPPING TO -10F FOR AREAS NEAR CO/WY BORDER. H85-H5 THICKNESS BACKS UP THIS THINKING AS GFS SHOWS 100DM DROP IN THICKNESS VALUE. OTHER AREAS WILL SEE SOME DROPS IN TEMPS BUT MOFFAT AND RIO BLANCO COUNTY LOOK TO HAVE THE BRUNT OF COLD WX. ONCE SYSTEMS MOVE OUT LATE TUE NIGHT...WEAK AREA OF HIGH PRESSURE WILL BUILD IN PROVIDING QUIET WEATHER AFTER UNSETTLED FEW DAYS. && .AVIATION... IFR CONDITIONS IN LOW CLOUDS AND FOG HAVE FORMED IN THE UINTA BASIN IMPACTING KVEL AIRPORT AGAIN TONIGHT AND WILL PERSIST THRU TOMORROW MORNING. PATCHY FOG WITH LOCAL MVFR VIS WILL ALSO BE POSSIBLE ALONG THE COLORADO RIVER UNTIL MID MORNING TO INCLUDE KGJT...KRIL...AND KEGE. KASE CURRENTLY REPORTING IFR CONDITIONS AS LIGHT SNOW HAS DROPPED CIGS AND VIS IN RESPONSE TO SYSTEM TO S. EXPECT THESE SNOWSHOWERS TO CONTINUE THRU NOON TIMEFRAME. EXPECT ALL TAF SITES TO BE MVFR BY NOON AND VFR A FEW HOURS LATER. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && SHORT TERM...MC LONG TERM....TGR AVIATION.....TGJT
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 603 AM MST THU FEB 4 2010 COZ001>014-017>023-UTZ022>025-027>029-051402- ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES- CENTRAL COLORADO RIVER BASIN- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR- EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS- ELKHEAD AND PARK MOUNTAINS-FLAT TOPS- FOUR CORNERS/UPPER DOLORES RIVER- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS- GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN- NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER- ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH- SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU- UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY- UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS- 603 AM MST THU FEB 4 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT PATCHY FOG IS POSSIBLE IN SOME OF THE VALLEY AREAS THIS MORNING... ESPECIALLY IN THE UINTA BASIN IN NORTHEAST UTAH...AND ON THE GRAND FLAT IN EAST CENTRAL UTAH. VISIBILITY MAY FALL BELOW ONE MILE AT ISOLATED LOCATIONS. SNOW SHOWERS WILL DEVELOP OVER THE MOUNTAINS TODAY...WITH LIGHT ACCUMULATIONS MAINLY OVER THE NORTHERN MOUNTAINS. SNOW WILL TAPER OFF TO SCATTERED SHOWERS LATER TONIGHT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH TUESDAY PRECIPITATION WILL START FRIDAY NIGHT OVER THE NORTHERN AND CENTRAL MOUNTAINS AS HIGH PRESSURE BREAKS DOWN. BY SATURDAY...NEXT DISTURBANCE WILL BRING PRECIPITATION OVER ENTIRE CWA...ESPECIALLY SAN JUANS AND HIGHER ELEVATIONS IN UTAH. THIS SYSTEM WILL MOVE OUT OF THE AREA BY SUNDAY AFTERNOON AS ANOTHER SYSTEM DROPS DOWN FROM THE NORTH CAUSING PRECIPITATION OVER CONTINENTAL DIVIDE THROUGH TUESDAY. SIGNIFICANT SNOW ACCUMULATION IS POSSIBLE THROUGH THE PERIOD FOR VARIOUS AREAS OF COLORADO AND UTAH. .SPOTTER INFORMATION STATEMENT SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
613 AM MST THU FEB 04 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
0607 AM SNOW OPHIR 37.86N 107.83W
02/04/2010 M3.0 INCH SAN MIGUEL CO AVALANCHE FCSTR
24 HOUR SNOWFALL AMOUNT. CURRENTLY SNOWING VERY
LIGHTLY.
&&
EVENT NUMBER GJT1000152
MALEKSAThe national radar mosaic for the moment the first event began.
2 dense fog. Local standard time, as filed.
Widespread dense fog reduced visibilities to below one-quarter mile.
Dense fog reduced visibilities in some areas to below one-quarter mile.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2010Every state in 2010This day in weather historyWarnings in Utah, February 2010
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: 210571, 210572.