A late season storm system brought heavy snow to portions of the North-Central Mountains and Front Range Foothills. Overall storm totals ranged from 10 to 21 inches.
Every event with a place to put it; 7 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 late season storm system brought heavy snow to portions of the North-Central Mountains and Front Range Foothills. Overall storm totals ranged from 10 to 21 inches. Across the Urban Corridor, storm totals ranged from 2 to 4 inches. In Fort Collins, the heavy snow broke tree branches around the city.
In the North-Central Mountains storm totals included: 14 inches at Bear Lake, 13 inches at Lake Eldora, 11 inches at Arapahoe Ridge, Lake Irene, Roach and Willow Creek SNOTELS; 12 inches, 16 miles northwest of Grand Lake; with 10 inches at Cameron Pass and Never Summer.
In the Front Range Foothills, storm totals included: 21.5 inches just east of Buckhorn Mountain; 18 inches, 5 miles south-southeast of Drake; 15 inches, 8 miles southwest of Estes Park and 7 miles east-northeast of Red Feather Lakes; 14.5 inches, 7 miles north of Glen Haven; 12.5 inches near Estes Park; with 12 inches, 3 miles west-northwest of Pingree Park.
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 11, 3:00 AM MST, 8 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 400 AM MDT TUE MAY 11 2010 .SHORT TERM...UPPER LOW HAS MOVED ONSHORE AND THERE IS VERY GOOD AGREEMENT AMONGST ALL THE MODELS AS THE NAM HAS COME IN LINE WITH THE GFS/ECMWF. THE AGREED UPON TRACK TAKES THE UPPER LOW ACROSS SOUTHERN UTAH TODAY AND THEN NORTHEAST THROUGH NORTHWEST COLORADO AND INTO SOUTHEAST WYOMING TONIGHT INTO WEDNESDAY MORNING. MEANWHILE...THE MID LEVEL CIRCULATION CENTER IS EXPECTED TO REDEVELOP EAST OF THE ROCKIES JUST SOUTH OF DENVER. THIS SHOULD BRING SUFFICIENT UPSLOPE AND COMBINED WITH THE STRONG LIFT SHOWN IN THE Q-G FIELDS SHOULD PROVIDE FOR A WIDESPREAD MODERATE TO HEAVY PRECIPITATION EVENT...NORTH OF THE MID LEVEL CIRCULATION CENTER AND LEFT OF THE UPPER LEVEL JET AXIS. FARTHER SOUTH...AND GENERALLY ALONG A SUMMIT COUNTY TO DENVER TO AKRON LINE...THERE IS A MUCH HIGHER PROBABILITY OF A SIGNIFICANT DRY SLOT SHUTTING DOWN THE HEAVIER PRECIPITATION. EVEN THOUGH THE MODELS REMAIN IN EXCELLENT AGREEMENT...THERE IS STILL SOME UNCERTAINTY IN THE FORECAST SINCE ANY SLIGHT SHIFT OF THE UPPER LEVEL DRY SLOT OR MID LEVEL CIRCULATION REDEVELOPMENT COULD HAVE LARGE IMPLICATIONS ON PRECIPITATION AMOUNTS. AT THIS TIME...THE PALMER DIVIDE HAS SLIM PROBABILITIES OF REACHING ANY SORT OF HIGHLIGHT CRITERIA SO HAVE CANCELLED THE WATCH THERE. IN THE SOUTHERN FOOTHILLS AND SUMMIT COUNTY AREA...THERE WILL LIKELY BE A LARGE VARIATION IN POTENTIAL SNOW TOTALS WITH THE HEAVIEST AMOUNTS NORTH OF THE I-70 CORRIDOR AND A SHARP CUTOFF TO THE SOUTH. HAVE OPTED TO ISSUES WINTER WEATHER ADVISORIES THERE...BUT EVEN THAT MAY BE OVERDONE IF STORM TRACK IS SLIGHTLY FARTHER NORTH. MEANWHILE... IN THE NORTHERN FRONT RANGE FOOTHILLS AND NORTHERN MOUNTAINS...THE LIKELIHOOD OF HEAVY SNOW IS MUCH GREATER SO HAVE CONTINUED THE WARNINGS THERE WITH 12 TO 24 INCHES EXPECTED... HEAVIER THE FARTHER NORTH ONE GOES. FINALLY...RAIN/SNOW ISSUES WILL BE TOUGH IN THE LOWER ELEVATIONS. LATEST INDICATIONS ARE THAT RAIN SHOULD TURN OVER TO MOSTLY SNOW IN THE FORT COLLINS TO CHEYENNE CORRIDOR BY MIDNIGHT...AND THEN DOWN INTO DENVER IN THE EARLY MORNING HOURS CLOSER TO 3-6 AM. FORTUNATELY...BY THE TIME TEMPERATURES GET COLD ENOUGH IN DENVER MOST OF THE HEAVIER PRECIPITATION SHOULD BE DONE WITH...BUT ONLY A COUPLE INCHES OF HEAVY WET SNOW COULD STILL BREAK TREE LIMBS. IN THE FORT COLLINS AREA...THERE IS A HIGHER PROBABILITY OF SIGNIFICANT HEAVY WET SNOW...BUT ENOUGH UNCERTAINTY WITH TEMPERATURES TO KEEP THE WINTER STORM WATCH IN PLACE FOR EASTERN LARIMER COUNTY AND NORTHWEST WELD COUNTY. A NARROW CORRIDOR ALONG THE WYOMING BORDER COULD STILL SEE A FOOT OF HEAVY WET SNOW IF TEMPERATURES REMAIN JUST COLD ENOUGH. .LONG TERM...UPPER LOW WILL BE LIFTING OUT OF THE STATE THROUGH TOMORROW WITH SUBSIDENCE EXPECTED TO BECOME DOMINANT ACROSS THE FORECAST AREA BY AFTERNOON. THIS SHOULD BRING A DECREASE TO THE PRECIPITATION AS THE DAY PROGRESSES. HOWEVER...RELATIVE HUMIDITY LEVELS ARE FORECAST TO REMAIN MOIST...HELPING TO MAINTAIN AT LEAST A CHANCE OF ONGOING LIGHT PRECIPITATION. TEMPERATURES AT LOW AND MID LEVELS WILL BE AT THEIR LOWEST THROUGH TOMORROW AND TOMORROW EVENING...SO THE PLAINS MAY SEE ANYTHING BETWEEN A CHILLY RAIN AND A WET SNOWFALL. HOWEVER...ACCUMULATIONS ON THE PLAINS SHOULD BE LIMITED BY THE GENERALLY LIGHT INTENSITY OF THE PRECIPITATION. IN THE MOUNTAINS...UP TO A COUPLE INCHES OF ADDITIONAL SNOWFALL IS POSSIBLE FROM PRIMARILY OROGRAPHIC SNOW SHOWER ACTIVITY. FOR WEDNESDAY AND BEYOND...THE MODELS HAVE BACKED OFF ON QPF AMOUNTS SO IT APPEARS THAT NO HIGHLIGHTS WILL BE NECESSARY BEYOND EARLY WEDNESDAY. AFTER THE CHILLY TEMPERATURES THROUGH WEDNESDAY NIGHT...A GRADUAL WARMING TREND IS EXPECTED WHICH WILL CONTINUE THROUGH THE WEEKEND. WEAK UPPER TROFFINESS IS FORECAST TO CONTINUE OVER THE DESERT SOUTHWEST WITH WEAK SOUTHWESTERLY FLOW ALOFT ACROSS COLORADO. THE AIRMASS ACROSS THE STATE WILL GRADUALLY DRY AND MODERATE IN THE ABSENCE OF ANY REINFORCING COLD AIR INTRUSIONS. BY THE WEEKEND...SURFACE HIGH PRESSURE BUILDING OVER THE CENTRAL AND SOUTHERN PLAINS MAY BEGIN MOVING SUBTROPICAL MOISTURE OVER THE HIGH PLAINS...BRINGING ABOUT A TRANSITION TO A MORE SUMMER-LIKE WEATHER PATTERN. FOR THE TIME BEING...WILL LEAVE THE FORECAST AS IS...WITH THE MENTION OF A FEW AFTERNOON SHOWERS EACH AFTERNOON THROUGH SATURDAY. && .AVIATION...STRATUS IS SPREADING AND DEVELOPING SOUTHWESTWARD ACROSS THE AREA EARLY THIS MORNING. THERE IS SOME VARIABILITY NOTED FROM UPSTREAM OBS ON CEILING HEIGHTS...BEST ESTIMATE IS THAT A LAYER AROUND 4000 FEET PREVAILS THIS MORNING...BUT AREAS OF LOWER CEILINGS TEMPORARILY DROPPING TO AROUND 1000 FEET. AT THIS TIME...FOG THREAT AND LOWER VISIBILITIES SEEMS LOW WITH THE OTHER CLOUD DECKS IN PLACE...BUT T/TD SPREADS ARE LOW SO WILL MONITOR. RAIN EXPECTED TO DEVELOP WITH LOWERING CEILINGS AND WIDESPREAD IFR CONDITIONS DEVELOPING THIS AFTERNOON/EARLY EVENING IN THE 21Z-03Z PERIOD...EARLIEST IN THE WESTERN SECTIONS OF DENVER AND LATEST FARTHER SOUTHEAST TOWARD KAPA AND KDEN. RAIN WILL MIX OR CHANGE TO SNOW AFTER MIDNIGHT WITH ACCUMULATIONS OF 1-3 INCHES POSSIBLE IN THE GRASS. && .BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING FOR THE NORTHERN FRONT RANGE MOUNTAINS NOON TODAY UNTIL NOON WEDNESDAY... ZONE 33. WINTER STORM WARNING FOR THE NORTHERN FRONT RANGE FOOTHILLS 3 PM MDT TODAY UNTIL NOON WEDNESDAY...ZONE 35. WINTER WEATHER ADVISORY FOR THE SOUTHERN FRONT RANGE FOOTHILLS AND SUMMIT COUNTY AREA 6 PM MDT TODAY UNTIL 6 AM MDT WEDNESDAY...ZONES 34 AND 36. WINTER STORM WATCH TONIGHT AND WEDNESDAY MORNING FOR EASTERN LARIMER COUNTY AND NORTHWESTERN WELD COUNTY...ZONE 38. BARJENBRUCH/KDRBY
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1047 AM MDT TUE MAY 11 2010 COZ030>051-121200- 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- 1047 AM MDT TUE MAY 11 2010 ...WINTER STORM WARNINGS...WATCHES...AND ADVISORIES IN EFFECT FOR THE FRONT RANGE MOUNTAINS...FOOTHILLS...AND FORT COLLINS AREA... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT THE LATEST STORM WILL MOVE INTO COLORADO TODAY THROUGH WEDNESDAY RAIN AND SNOW WILL BE DEVELOPING AND SPREADING EASTWARD ACROSS THE FORECAST AREA. THE HEAVIEST PRECIPITATION IS EXPECTED TO OCCUR NORTH OF THE INTERSTATE 70 CORRIDOR...WITH AMOUNTS TAPERING OFF QUICKLY FARTHER SOUTH. HEAVY SNOWFALL OF 1 TO 2 FEET CAN BE EXPECTED IN THE MOUNTAINS AND FOOTHILLS OF LARIMER AND BOULDER COUNTIES. SNOWFALL AMOUNTS OF 6 TO 14 INCHES ARE EXPECTED ACROSS THE LOWER ELEVATIONS OF EASTERN LARIMER AND NORTHWESTERN WELD COUNTIES INCLUDING FORT COLLINS. THE HEAVY SNOW COULD BREAK TREE LIMBS AND CAUSE POWER OUTAGES. ACROSS THE REST OF THE PLAINS INCLUDING DENVER...BOULDER... GREELEY...AND POINTS EASTWARD ACROSS THE PLAINS...MOST OF THE PRECIPITATION WILL FALL IN THE FORM OF RAIN. HOWEVER...TEMPERATURES ARE EXPECTED TO TURN COLD ENOUGH FOR SOME SNOWFALL AND POSSIBLE ACCUMULATIONS OF 1 TO 4 INCHES ON GRASSY SURFACES AFTER MIDNIGHT THROUGH LATE WEDNESDAY MORNING. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A MIX OF RAIN AND SNOW ON THE PLAINS AND SNOW IN THE MOUNTAINS WILL BE DECREASING THROUGH THE DAY WEDNESDAY. ADDITIONAL SNOW AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE ON THE PLAINS WITH UP TO 4 INCHES IN THE MOUNTAINS. COLD TEMPERATURES ARE EXPECTED WEDNESDAY NIGHT... FALLING TO NEAR OR BELOW FREEZING. A GRADUAL WARMING AND DRYING TREND WILL THEN BEGIN ON THURSDAY AND CONTINUE THROUGH THE WEEKEND. HOWEVER...A LOW LEVEL OF AFTERNOON AND EVENING THUNDERSTORM ACTIVITY WILL CONTINUE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. RJK/GIMMESTAD
The national radar mosaic for the moment the first event began.
5 winter weather, 2 winter storm. Local standard time, as filed.
Storm totals ranged from 4 to 9 inches.
Storm totals ranged from 8 to 13 inches.
Storm totals ranged from 4 to 13 inches, the heavier amounts were more localized.
Storm totals ranged from 9 to 21.5 inches of snowfall.
Storm totals ranged from 4 to 7 inches.
Storm totals ranged from 2 to 4 inches.
Storm totals ranged from 2 to 4 inches.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2010Every state in 2010This day in weather historyWarnings in Colorado, May 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: 225017, 225018, 225019, 225020, 225021, 225022, 225023.