A spring snowstorm brought heavy snow to the mountains, foothills and Palmer Divide. 5 inches, 3 miles east of Franktown and 3 miles south of Golden and 10 inches, 10 miles north of Elizabeth.
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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 spring snowstorm brought heavy snow to the mountains, foothills and Palmer Divide. The heaviest snowfall occurred in the Front Range Foothills and Palmer Divide where storm totals included: 18 inches, 4 miles south-southeast of Pinecliffe; 16 inches at Coal Creek Canyon; 15 inches, 4 miles west-southwest of Eldorado Springs; 13 inches at Gold Hill, 12 inches, 4 miles west-southwest of Conifer and 4 miles northwest of Elizabeth; 11.5 inches, 6 miles southwest of Evergreen and 4 miles east-northeast of Nederland; 11 inches, 3 miles east of Jamestown and 10.5 inches, 3 miles east of Franktown and 3 miles south of Golden and 10 inches, 10 miles north of Elizabeth. In the mountains storm totals included: 12 inches at Berthoud Pass, 10.5 inches at Breckenridge, 10 inches at Hourglass Lake, 9 inches at Lake Irene with 8 inches at Joe Wright.
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 May 10, 2:44 PM MST, 8 hours 16 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO ISSUED BY NATIONAL WEATHER SERVICE PUEBLO CO 344 PM MDT TUE MAY 10 2011 .SHORT TERM... (TONIGHT AND WEDNESDAY) ...SNOW ALONG EASTERN SLOPES OF FRONT RANGE TONIGHT AND WEDNESDAY... .TONIGHT AND WEDNESDAY...UPPER LOW SPINNING OVER ARIZONA WILL DRIFT TO THE NORTHEAST TONIGHT AND WEDNESDAY...PASSING OVER SOUTHERN AND SOUTH CENTRAL COLORADO ON WEDNESDAY. ALL MODELS SHOW STRONG NORTHEAST UPSLOPE AT 700MB AND BELOW DEVELOPING LATE TONIGHT AND CONTINUING INTO WEDNESDAY. THE DEEP NORTHEAST FLOW IS FAVORABLE FOR PRECIPITATION ALONG THE EASTERN SLOPES OF THE FRONT RANGE....HOWEVER THE FORECAST IS NOT THAT SIMPLE. DRY SLOT ALOFT TRIES TO WORK NORTH AND NORTHWESTWARD AROUND THE UPPER LOW AND INTO THE REGION. MODEL SOUNDINGS ARE NEARLY ISOTHERMAL FROM AROUND 750 MB TO 550 MB WHICH WILL HAMPER ANY CONVECTIVE ENHANCEMENT TO THE SNOW. IN ADDITION...THE MODEL SOUNDINGS DO NOT MOISTEN THE ATMOSPHERE MUCH ABOVE THE -15C LEVEL WHERE DENDRITIC GROWTH IS THE BEST. HOWEVER...LATEST NAM HAS AROUND 1 INCH OF LIQUID FOR THE EASTERN SLOPES FOR TONIGHT AND WEDNESDAY. EVEN IF THE NAM IS TOO WET BY 50%...THIS IS STILL ENOUGH MOISTURE TO GET SNOW ADVISORY CRITERIA. ISSUED A SNOW ADVISORY FOR THE EASTERN SLOPES OF THE FRONT RANGE. ANTICIPATE THE HEAVIEST SNOWFALL WILL BE AROUND 7000 FEET AND ABOVE. THERE IS A CHANCE SNOW LEVEL MAY BRIEFLY GET AS LOW AS 5000 FEET IN SOME OF THE HEAVIER BANDS OF SNOW...BUT DO NOT ANTICIPATE ANY ACCUMULATIONS THIS LOW. AS THE UPPER LOW MOVES INTO SOUTHEAST COLORADO BY WEDNESDAY AFTERNOON...THE THREAT FOR HEAVIER PRECIPITATION WILL MOVE INTO EASTERN COLORADO. --WOLYN-- .LONG TERM... (WEDNESDAY NIGHT THROUGH TUESDAY) ALL THE MODELS SUGGEST THE UPPER LOW WILL INTENSIFY OVER EAST CENTRAL COLORADO WEDNESDAY EVENING AND SLOWLY DRIFT TO THE EAST. PRECIPITATION WILL WRAP WEST OF THE LOW. ALL THE MODELS ARE GENEROUS WITH QPF OVER PORTIONS OF THE EASTERN PLAINS WEDNESDAY NIGHT AND THURSDAY. THE BANDS OF HEAVIER PRECIPITATION MAY NOT LEAVE EASTERN COLORADO UNTIL THURSDAY NIGHT. TEMPERATURES ON THE PLAINS LOOK TO BE SLIGHTLY TOO WARM FOR SNOW. FURTHER WEST...DOWNSLOPE NORTHWEST FLOW WILL LIMIT PRECIPITATION NEAR THE MOUNTAINS. WITH DRIER AIR MOVING INTO THE MOUNTAINS...DO NOT ANTICIPATE MUCH QPF. FRIDAY THROUGH TUESDAY...OMEGA BLOCK DEVELOPS WITH COLORADO BEING UNDER A RIDGE ALOFT. ALL THE MODELS SUGGEST UPSLOPE OVER THE REGION DURING THE WEEKEND WITH SOME CONVECTION POSSIBLE OVER THE PLAINS AND EASTERN MOUNTAINS. THE 12Z GFS SOLUTION FOR SATURDAY LOOKS SUSPICIOUS...AND BELIEVE THE WEAKER DISTURBANCE IN THE EC IS MORE REALISTIC. --WOLYN-- && .AVIATION... AT THE SURFACE...LOW DEVELOPED OVER SOUTHEAST COLORADO TODAY WITH INVERTED SURFACE TROF EXTENDING THRU NORTHERN COLORADO. SURFACE TROF IN VICINITY OF THE TAF SITES EARLY THIS AFTERNOON HAS MADE FOR VARIABLE SURFACE WIND DIRECTION. ALOFT...WATER VAPOR IMAGERY SHOWS TO CLOSED CIRCULATIONS...ONE IN EASTERN MT AND ONE NEAR SOUTHERN NV. AS SOUTHERN UPPER LOW LIFTS NORTHEAST OVERNIGHT...STRONG COLD FRONT WILL MOVE SOUTH THROUGH NORHTERN COLORADO BETWEEN 03Z AND 06Z. CEILINGS WILL LOWER AFTER FROPA WITH AREAS OF PRECIPITATION DEVELOPING IN THE NORTHERN MOUNTAINS AND FRONT RANGE. COLD TEMPS ALOFT WITH THIS SYSTEM WILL MEAN PRECIPITATION WILL LIKELY MIX WITH OR CHANGE TO SNOW AT LEAST FOR A TIME BETWEEN 09Z AND 13Z. SNOW ACCUMULATIONS WILL BE MINIMAL AT THE LOWER ELEVATIONS DUE TO THE WARM GROUND. KDEN...SURFACE WINDS REMAINING SOUTHEAST TO SOUTH THROUGH THE EVENING. FROPA AROUND 03Z WITH STRONG NORTHERLY WIND SHIFT. CIGS LOWERING BETWEEN 03Z AND 06Z WITH AREAS OF PRECIPITATION DEVELOPING. MIXED RAIN AND SNOW POSSIBLE THROUGH 13Z...WITH LITTLE CHANCE OF ACCUMULATION ON PAVED SURFACES. STARK && .HYDROLOGY...QPF OVER THE FOUR MILE BURN SCAR MAY APPROACH A THIRD TO HALF AN INCH OF LIQUID THROUGH WEDNESDAY AFTERNOON. SOME OF THE PRECIPITAION WILL FALL AS SNOW WHICH WILL DELAY RUNOFF IN THE BURN SCAR. WILL HAVE TO MONITOR FOR THE POTENTIAL OF LOCALLY HEAVIER PRECIPITATION OVER THIS REGION. --WOLYN-- && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MDT WEDNESDAY FOR COZ033>036. && 06/06
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 655 PM MDT TUE MAY 10 2011 COZ030>051-111200- 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- 655 PM MDT TUE MAY 10 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT A STORM SYSTEM OVER SOUTHWEST COLORADO WILL MOVE SLOWLY EAST INTO SOUTHEAST COLORADO OVERNIGHT. SNOW SHOWERS WILL INCREASE IN THE FOOTHILLS AND MOUNTAINS ESPECIALLY AFTER MIDNIGHT WITH ACCUMULATIONS BY SUNRISE RANGING FROM 3 TO 6 INCHES IN THE MOUNTAIN WITH 2 TO 4 INCHES IN THE FOOTHILLS. AT LOWER ELEVATIONS RAIN SHOWERS WILL BECOME LIKELY AFTER MIDNIGHT WITH SOME SNOW MIXING IN NEAR THE FOOTHILLS AND OVER THE PALMER DIVIDE AFTER 3 AM. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE STORM SYSTEM WILL MOVE SLOWLY NORTHEAST INTO WESTERN KANSAS BY WEDNESDAY NIGHT. THUS SNOW WILL CONTINUE IN THE MOUNTAINS AND FOOTHILLS ON WEDNESDAY WITH ADDITIONAL ACCUMULATIONS OF 3 TO 6 INCHES IN THE MOUNTAINS AND 2 TO 4 INCHES IN THE FOOTHILLS. SOME SNOW MAY OCCUR EARLY IN THE MORNING NEAR THE FOOTHILLS WITH UP TO AN INCH ON GRASSY AREAS. OVER THE PALMER DIVIDE ACCUMULATIONS OF 2 TO 4 INCHES WILL BE POSSIBLE. RAIN SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE OVER THE NORTHEAST PLAINS THROUGH THE AFTERNOON. BY WEDNESDAY NIGHT SNOW WILL GRADUALLY END IN THE MOUNTAINS AND FOOTHILLS BUT RAIN WILL CONTINUE OVER THE NORTHEAST PLAINS. BY THURSDAY HE STORM SYSTEM WILL MOVE ACROSS KANSAS WITH RAIN GRADUALLY ENDING OVER THE NORTHEAST PLAINS BY THURSDAY MORNING. IN THE MOUNTAINS THERE WILL BE A CHANCE OF SNOW SHOWERS. FOR FRIDAY IT SHOULD BE DRY WITH WARMER TEMPERATURES. OVER THE WEEKEND THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY IN THE MOUNTAINS WITH SEASONAL TEMPERATURES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT. RPK
The national radar mosaic for the moment the first event began.
3 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 2011Every state in 2011This day in weather historyWarnings in Colorado, May 2011
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: 312806, 312807, 312810, 312811, 312813.