A narrow but intense band of heavy snow developed over part of the Urban Corridor. The band extended from northwest of Lyons, through northwest Denver and into Aurora, Parker and Elizabeth.
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 BOU wrote it up.
A narrow but intense band of heavy snow developed over part of the Urban Corridor. The band extended from northwest of Lyons, through northwest Denver and into Aurora, Parker and Elizabeth. Snowfall rates of 2 to 4 inches per hour were observed under the most intense part of the band. Storm totals included: 9.2 inches near Westminster; 9 inches, 5 miles east of Boulder; 8 inches in Federal Heights and 4 miles northwest of Parker; 7.5 inches near Aurora and 11 miles southeast of Estes Park; 7 inches near Elizabeth, Lafayette and Northglenn; 6.5 inches in southeast Denver; 6 inches, near Commerce City, Denver Stapleton and 4 miles northwest of Lyons. Storm totals elsewhere ranged from 3 to 5 inches.
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 Denver/Boulder, CO wrote its last area forecast discussion before the first event at Jan 31, 10:59 PM MST, 1 hour 1 minute earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1059 PM MST SAT JAN 31 2015 .UPDATE... ISSUED AT 1052 PM MST SAT JAN 31 2015 BANDED HEAVY SNOW HAS DEVELOPED OVER THE BOULDER AND DENVER AREAS AND EXTENDING SOUTHWARD INTO DOUGLAS AND ELBERT COUNTIES. REPORTS OF SNOWFALL RATES EXCEEDING 1"/HR IN BROOMFIELD. BANDED SNOW IS JET INDUCED AND FEEL THIS MAY BE SLOWER TO MOVE OUT DESPITE SOME DRYING OVER NORTHERN PORTIONS OF CWA. HAVE ISSUED WINTER WEATHER ADVISORY FOR TONIGHT FOR BOULDER...BROOMFIELD...DENVER AND CASTLE ROCK AREAS. HEAVY SNOW LIKELY THROUGH ABOUT 3 AM THEN DIMINISHING FROM NORTH TO SOUTH. UPDATE ISSUED AT 827 PM MST SAT JAN 31 2015 RADAR HAS INDICATED AN INCREASE IN SNOW SHOWERS OVER LARIMER AND WELD COUNTIES DURING THE PAST HOUR WHILE MOUNTAIN SNOW SHOWERS ALSO SHOWING AN UP TIC IN COVERAGE. THIS IN RESPONSE TO STRONG JET ALOFT WHICH HAS JUST NOSED INTO NORTHERN COLORADO. STRONGER COLD FRONTAL PUSH APPEARS TO BE ACROSS FAR SOUTHEAST WYOMING AS WINDS NOW GUSTING TO 31KT AT CYS. THESE STRONGER NORTHEAST WINDS WILL PUSH SOUTHWARD ACROSS THE NORTHEAST PLAINS THROUGH THE NIGHT AS WINDS SHIFT AND INCREASE FROM NORTH AND NORTHEAST. EXPECT SNOW SHOWERS TO EXPAND SOUTHWARD INTO THE DENVER AREA IN NEXT FEW HOURS WITH BEST CHANCE OF ACCUMULATING SNOW FROM 11 PM TO 4 AM. SHOWERS HAVE A CONVECTIVE NATURE AS AIRMASS HAS DESTABILIZED A BIT WITH 00Z DEN SOUNDING SHOWED QUITE A BIT OF COLD ADVECTION ALOFT DURING THE DAY. MAIN CHANGE TO FORECAST WAS TO TWEAK EVENING HOURS WITH LATEST TRENDS BUT OVERALL SNOW AMOUNTS STILL LOOK GOOD IN THE 1-3 INCH RANGE. HIGHEST AMOUNTS WILL BE UNDER BANDED SNOWFALL. ALSO INCREASED SNOW CHANCES IN THE HIGHER MOUNTAINS WITH GOOD OROGRAPHIC FLOW ESPECIALLY IN ZONE 33. SNOW WILL DECREASE LATER TONIGHT AS JET MOVES EAST AND STRONGER SUBSIDENCE DEVELOPS WITH DIMINISHING UPSLOPE FLOW. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 154 PM MST SAT JAN 31 2015 SHOWER ACTIVITY DEVELOPING THIS AFTN AS A SPLITTING TROUGH WITH WEAK DEFORMATION ZONE OVER THE CWA SHIFTS TO THE EAST. BEST CHC OF SNOW WL BE OVER THE PALMER DIVIDE SOUTH AND EAST OF DENVER. DRIER AIR WILL PUSH IN FROM THE NORTHWEST AHEAD OF THE NEXT SYSTEM. THE NEXT SYSTEM DROPS INTO NORTHERN COLORADO FM WYOMING THIS EVENING. THE COLD FRONT IS EXPECTED TO REACH DENVER IN THE 03-04Z TIME FRAME WITH NORTH TO NORTHEAST UPSLOPE WINDS IN ITS WAKE. IN ADDITION THE NOSE OF 90 KT UPPER LEVEL JET WILL TRANSLATE EAST ACROSS NORTHERN COLORADO TONIGHT INTO SUNDAY MORNING SO THERE COULD BE A PERIOD OF SOME ENHANCED SNOW BANDS. THE BEST WINDOW FOR SNOW WL BE FROM 05Z-12Z. INCREASING SUBSIDENCE WILL OCCUR ON SUNDAY WITH A DRIER NORTHWESTERLY FLOW ALOFT OVER NORTHERN COLORADO. TEMPERATURES WILL BE RUNNING COOLER THAN NORMALS WITH HIGHS GENERALLY IN THE 30S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 154 PM MST SAT JAN 31 2015 MOISTURE AND WIND INCREASE OVER THE MOUNTAINS MONDAY MORNING AS A MOIST NORTHWESTERLY FLOW ALOFT SETS UP OVER COLORADO. THIS PATTERN WILL BRING PERIODS OF SNOW TO THE HIGH COUNTRY FROM MONDAY THROUGH WEDNESDAY. SNOWFALL AMOUNTS SHOULD REMAIN ON THE LIGHT SIDE DUE TO POOR LAPSE RATES AND LACK OF MOISTURE DEPTH AT TIMES. HOWEVER...COULD SEE BRIEF PERIODS OF HEAVIER SNOW AT TIMES. WINDY CONDITIONS ARE ALSO EXPECTED OVER THE MOUNTAINS AND FOOTHILLS FROM EARLY MORNING MONDAY THROUGH NOON ON TUESDAY. LOOKS LIKE IT WILL BE WINDIEST FROM THE EASTERN SLOPES OF THE MOUNTAINS INTO THE HIGHER FOOTHILLS. AT THIS TIME IT LOOKS LIKE WINDS SHOULD REMAIN BELOW WARNING CRITERIA. THIS DOWNSLOPE FLOW WILL PRODUCE MILD AND DRY WEATHER FOR AREAS EAST OF THE MOUNTAINS MONDAY AND TUESDAY. BY WEDNESDAY...THE MODELS BEGIN TO DIVERGE SOMEWHAT. BOTH THE GFS AND THE ECMWF SHOW AN UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT MOVING ACROSS THE NORTHERN AND CENTRAL ROCKIES. THE GFS IS MORE AMPLIFIED WITH THIS SYSTEM AND PLACES THE UPPER JET 300 MILES FURTHER TO THE SOUTH THAN THE ECMWF. AS A RESULT...THE GFS HAS MUCH MORE QG LIFT OVER NORTHERN COLORADO...WITH THE ECMWF HAVING WEAKER LIFT FURTHER TO THE NORTH OVER WYOMING. IF THE GFS PANS OUT...WOULD SEE HEAVY BANDS OF SNOW OVER NORTHERN SECTIONS OF THE NORTHEASTERN PLAINS FROM LARIMER COUNTY EASTWARD INTO SEDGWICK AND PHILLIPS COUNTIES. THE ECMWF SHOWS MUCH LESS SNOW AND KEEPS IT CONFINED TO AREAS JUST ALONG THE WYOMING AND NEBRASKA BORDERS. DO TO THE UNCERTAINTY OF THE MODELS...HAVE ONLY RAISED POPS IN THESE AREAS TO SCATTERED. MODELS SHOW AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDING INTO THE ROCKY MOUNTAIN REGION BY LATE IN THE WORK WEEK WITH MUCH WARMER AND DRIER WEATHER MOVING INTO THE AREA. TEMPERATURES COULD POSSIBLY REACH THE LOWER 70'S ACROSS PORTIONS OF THE FRONT RANGE URBAN CORRIDOR ON FRIDAY. THEREFORE...HAVE RAISED FRIDAY MAX TEMPS.| && .AVIATION...(FOR THE TAFS THROUGH 06Z SUNDAY EVENING) ISSUED AT 1052 PM MST SAT JAN 31 2015 THE HEAVY SNOW BAND HAS DEVELOPED OVER TERMINALS ESPECIALLY FROM BJC TO APA HOWEVER THERE IS AN EXTENSION OF THE HEAVIER SNOW AT DIA AS WELL. NEW TERMINAL FORECASTS HAVE HEAVY SNOW UNTIL AT LEAST 08Z AND MAY NEED TO BE EXTENDED IF THE BANDS DON'T MOVE MUCH. INCREASED SNOWFALL AMOUNTS OF 3 TO 6 INCHES AT BJC/APA AND 2-3 INCHES POSSIBLE AT DIA. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 AM MST SUNDAY FOR COZ039>041. && UPDATE...ENTREKIN SHORT TERM...COOPER LONG TERM...JK AVIATION...ENTREKIN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1010 AM MST SAT JAN 31 2015 COZ030>051-011715- JACKSON COUNTY BELOW 9000 FEET- WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET- GRAND AND SUMMIT COUNTIES BELOW 9000 FEET- SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/ NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET- SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/ GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET- JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET- CENTRAL AND SOUTHEAST PARK COUNTY- LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY- BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY- NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY- ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET- NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY- CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES- NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN COUNTY- SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY- LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY- 1010 AM MST SAT JAN 31 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT AREAS OF LIGHT SNOW WILL CONTINUE ACROSS THE MOUNTAINS THROUGH THE DAY. ON THE PLAINS...A FEW LIGHT RAIN OR SNOW SHOWERS WILL DEVELOP AS THE DAY PROGRESSES...MOST OF THESE HOLDING OFF UNTIL AFTERNOON. THE CHANCE OF ACCUMULATING SNOWFALL ON THE PLAINS WILL INCREASE LATE THIS EVENING BEHIND THE PASSAGE OF A COLD FRONT. THE AIRMASS WILL BECOME MORE UNSTABLE SO LOCALLY HEAVY AND BANDED SNOW SHOWERS WILL BE POSSIBLE. MOST LOCATIONS SHOULD SEE LESS THAN 1 INCH OF ACCUMULATION...BUT ANYWHERE HEAVIER BANDS SET UP COULD SEE A QUICK 2 TO 3 INCHES OF SNOWFALL AND HAZARDOUS TRAVEL CONDITIONS. AT THIS TIME...THE POTENTIAL FOR HEAVIER SHOWERS WOULD FAVOR THE WESTERN AND SOUTHERN DENVER SUBURBS INTO THE FOOTHILLS AND PALMER DIVIDE AREA FROM LATE THIS EVENING INTO THE PRE-DAWN HOURS SUNDAY. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY MAINLY DRY CONDITIONS ARE EXPECTED FOR SUNDAY WITH HIGHS IN THE 30S OVER NORTHEAST COLORADO. WINDY AND WARMER WEATHER WILL OCCUR BY MONDAY WITH A GOOD CHANCE OF SNOW IN THE MOUNTAINS. ONLY LIGHT ACCUMULATIONS ARE EXPECTED AT THIS TIME. TUESDAY WILL BE MILD AND DRY OVER NORTHEAST COLORADO WITH SOME LIGHT SNOW IN THE MOUNTAINS AND SOME GUSTY WINDS IN THE FOOTHILLS. A WEATHER DISTURBANCE MAY BRING COLDER TEMPERATURES ALONG WITH A CHANCE OF SNOW ON WEDNESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. HOWEVER...ANY REPORTS OF ACCUMULATING SNOWFALL WOULD BE APPRECIATED.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
1124 PM MST SAT JAN 31 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1121 PM SNOW 2 SSW BOULDER 40.00N 105.27W
01/31/2015 M3.4 INCH BOULDER CO NWS EMPLOYEE
NWS OFFICE. IN LAST 1.5 HOURS
1121 PM SNOW 1 NNW FEDERAL HEIGHTS 39.88N 105.03W
01/31/2015 M2.5 INCH ADAMS CO TRAINED SPOTTER
1105 PM SNOW LYONS 40.22N 105.27W
01/31/2015 M4.0 INCH BOULDER CO TRAINED SPOTTER
1103 PM SNOW LAFAYETTE 39.99N 105.10W
01/31/2015 M2.5 INCH BOULDER CO TRAINED SPOTTER
&&The national radar mosaic for the moment the first event began.
2 winter storm, 2 winter weather. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2015Every state in 2015This day in weather historyWarnings in Colorado, 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: 552317, 552318, 554233, 554234.