Another spring storm brought heavy snow to the mountains, with period of moderate to heavy snow to portions of the Front Range Foothills and Urban Corridor. 5 inches and near Silverthorne.
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.
Another spring storm brought heavy snow to the mountains, with period of moderate to heavy snow to portions of the Front Range Foothills and Urban Corridor. In the mountains and foothills, storm totals included: 18 inches at Niwot Ridge SNOTEL; 16.5 inches near Ward; 13 inches at Arapahoe Basin and Roach SNOTEL, 12 inches near Blackhawk; 11.5 inches near Nederland; 11 inches near Allenspark, Estes Park, Grizzly Peak and Loveland Ski Area; 10 inches at Cabin Creek, near Idaho Springs and Pinecliffe; with 9.5 inches and near Silverthorne.
Along the Urban Corridor storm totals included: 7.5 inches near Morrison; 7 inches at the National Weather Service Office in Boulder and Niwot; 6.5 inches near Arapahoe Park, Flat Iron Reservoir, Fort Collins and Superior; with 6 inches at Kassler, Lafayette and Lakewood.
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 Apr 22, 8:36 AM MST, 2 hours 24 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 936 AM MDT MON APR 22 2013 .UPDATE...HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORIES FOR ZONES 33>36 TO A WINTER STORM WARNING. HAVE ALSO ADDED ZONES 30..32 AND 38>41 IN A WINTER WEATHER ADVISORY FOR THIS AFTERNOON AND TONIGHT. COLD FRONT WILL BE MOVING INTO THE DENVER AREA BY 16Z WITH TEMPERATURES EXPECTED TO DROP SHORTLY AND SNOW DEVELOPING FOLLOWING THE PASSAGE OF THE FRONT. THE COMBINATION OF UPSLOPE...ENHANCED BANDING AS WELL AS SOME EMBEDDED THUNDERSTORMS ALL INGREDIENTS FOR HEAVY SNOW. NOT SURE THERE WILL BE MUCH ACCUMULATION IN THE URBAN CORRIDOR ON THE ROADWAYS THIS AFTERNOON BUT SOME SLUSH COULD BE ACCUMULATING BY THE EVENING COMMUTE. WET ROADS PRIOR TO THIS MAY BECOME ICY IN SPOTS...ESPECIALLY OVER BRIDGES AND OVERPASSES AS TEMPERATURES DROP TO INTO THE LOWER 30S THIS AFTERNOON. && .AVIATION...COLD FRONT WILL MAKE ITS WAY INTO THE DENVER AREA BY 16Z WITH GUSTY NORTH TO NORTHEAST WINDS FOLLOWING FROPA. CIGS WILL QUICKLY DETERIORATE SO HAVE MOVED UP TO TIMING FOR THE LOW CIGS AND VSBYS AS BANDS OF MODERATE TO HEAVY SNOW EXPECTED TO DEVELOP THIS AFTERNOON AND EVENING. STILL THINKING 2 TO 5 INCHES AT KDEN..WITH 5 TO 7 INCHES POSSIBLE NEAR KAPA AND KDEN BY 12Z TUESDAY MORNING. IF AN ENHANCED BAND OF SNOW SETS UP OVER KDEN FOR 2 TO 3 HOURS...THEN UP TO 7 INCHES A POSSIBILITY. CONDITIONS WILL BE WORST BETWEEN 22Z AND 06Z AS UPSLOPE AND BANDED SNOWFALL WILL BE BEST AT THAT TIME. && .PREV DISCUSSION... /ISSUED 509 AM MDT MON APR 22 2013/ SHORT TERM...EVERYTHING APPEARS TO BE ON TRACK FOR OUR NEXT SHOT OF WINTER WEATHER LATER TODAY AND TONIGHT. THE SURFACE COLD FRONT HAS RECENTLY MOVED THROUGH CASPER...WYOMING ON ITS WAY SOUTHWARD WITH A DECENT PRESSURE SURGE BEHIND IT. TEMPERATURES IN NORTHERN WYOMING ARE ALREADY IN THE LOWER AND MID 20S...SO A SHARP DROP IN TEMPERATURES IS EXPECTED LATER TODAY AFTER THE COLD FRONT MOVES THROUGH. MODELS SHOW THE COLD FRONT MOVING OVER NORTHEAST COLORADO FROM THE LATE MORNING THROUGH EARLY AFTERNOON WITH FRONTAL PASSAGE IN DENVER AROUND 20Z. THIS SHOULD ALLOW TEMPERATURES TO REACH THE MID AND UPPER 40S BEFORE FALLING TO THE LOWER AND MID 30S BEHIND THE FRONT. MODEL CROSS SECTIONS SHOW STRONG UPSLOPE FLOW DEVELOPING BEHIND THE FRONT AND CONTINUING OVERNIGHT. DEW POINTS ON THE PLAINS HAVE CREPT INTO THE MID AND UPPER 30S THIS MORNING WHICH WILL BE THE MOISTURE TO FEED INTO THE UPSLOPE FLOW LATER TONIGHT. IN ADDITION TO THE SURFACE FEATURES...THE 100+ KNOT JET HAS MOVED OVER THE STATE AS EXPECTED...WHICH WILL REMAIN OVER US THROUGH TONIGHT. THIS FEATURE WILL AID IN PRODUCING PRECIPITATION OVER THE MOUNTAINS AND ACROSS THE PLAINS THROUGH THIS AFTERNOON AND TONIGHT. SNOW SHOWERS HAVE BEEN DEVELOPING IN THE MOUNTAINS EARLY THIS MORNING AS EVIDENCE OF THE DYNAMIC LIFTING FROM THE JET ALOFT. FURTHER UPSTREAM...THE WATER VAPOR DOES NOT LOOK THAT MOIST...BUT INFRARED SATELLITE IMAGERY IS BEGINNING TO SHOW SOME MOISTENING OVER NORTHERN UTAH AND SOUTHWEST WYOMING. THIS WILL BE MOVING INTO THE NORTH CENTRAL MOUNTAINS LATER TODAY. WILL BE CHANGING THE WINTER STORM WATCH IN THE MOUNTAINS AND FOOTHILLS TO A WINTER WEATHER ADVISORY FROM NOON TODAY THROUGH TUESDAY MORNING. SNOW AMOUNTS OF 6 TO 10 INCHES LOOKS LIKE A GOOD BET IN THE HIGH COUNTRY. ACROSS THE PLAINS LATER TONIGHT...BANDED PRECIPITATION IS GOING TO BE A POSSIBILITY BECAUSE OF THE JET ALOFT. IT IS HARD TO TELL WHERE THESE BANDS ARE GOING TO SET UP...SO FOR NOW THE FORECAST WILL JUST TALK ABOUT 2 TO 5 INCH ACCUMULATIONS OVERNIGHT. LONG TERM...THE UPPER LEVEL TROUGH WILL STILL BE MOVING ACROSS THE AREA TUE MORNING WITH SOME MID LVL QG ASCENT HOWEVER THE UPSLOPE COMPONENT WILL BE VERY WEAK. THUS WILL SEE SOME LINGERING LIGHT SNOW THRU THE MORNING HOURS FM DENVER SOUTH TO THE PALMER DIVIDE AND IN THE FOOTHILLS AND MTN AREAS MAINLY SOUTH OF I-70. BY AFTN WITH LINGERING MOISTURE AND DECENT LAPSE RATES IN THE MTNS AND FOOTHILLS COULD SEE SOME SNOW SHOWERS REDEVELOP. OVER THE PLAINS DRIER AIR WILL BE IN PLACE BY AFTN SO WILL KEEP FCST DRY. AS FAR AS HIGHS OVERALL WILL KEEP READINGS IN THE 35 TO 40 DEGREE RANGE ACROSS NERN CO. FOR WED A WK DISTURBANCE IN NW FLOW ALOFT WILL MOVE ACROSS THE AREA HOWEVER MOISTURE WITH THIS FEATURE IS RATHER LIMITED SO WILL ONLY MENTION A SLIGHT CHC OF -SHSN IN THE MTNS. HIGHS ACROSS NERN CO SHOULD RISE INTO THE UPPER 40S TO LOWER 50S. BY THU A WK UPER LEVEL TROUGH WILL MOVE ACROSS THE SRN ROCKIES WHICH MAY LEAD TO A SLIGHT CHC OF -SHSN IN THE MTNS SOUTH OF I-70. FOR NOW WILL KEEP THE PLAINS DRY ALTHOUGH IF THIS FEATURE ENDS UP A LITTLE FURTHER NORTH THERE COULD BE A FEW LIGHT SHOWERS THU AFTN AND EVENING OVER THE PALMER DIVIDE AND SOUTH OF I-70. AS FOR HIGHS LOOKS LIKE READINGS OVER NERN CO SHOULD RISE BACK INTO THE LOWER 60S. FOR FRI AND SAT MAINLY DRY WNW FLOW ALOFT IS FCST OVER THE AREA. MEANWHILE TEMPS WILL CONTINUE TO RISE WITH HIGHS OVER NERN CO IN THE 60S ON FRI AND POSSIBLY NEAR 70 BY SAT. LITTLE CHANGE IS EXPECTED FOR SUN WITH MAINLY DRY CONDITIONS AND TEMPS NEAR 70 ACROSS NERN CO. AVIATION...HIGH CEILINGS WILL CONTINUE THROUGH EARLY AFTERNOON WHEN THE COLD FRONT COMES THROUGH WITH GUSTY WINDS COOLING TEMPERATURES. CEILINGS WILL RAPIDLY DROP TO MVFR AND THEN IFR AS SNOW SHOWERS DEVELOP IN THE HOUR OR SO AFTER FRONTAL PASSAGE. IFR CONDITIONS ARE EXPECTED TONIGHT DUE TO STRONG UPSLOPE WINDS AND A MOIST AIRMASS. SNOW ACCUMULATIONS COULD BE 1 TO 2 INCHES BY 7 PM AND THEN ANOTHER 3 TO 5 INCHES OVERNIGHT. IF A HEAVIER SNOW BAND SETS UP OVER THE AIRPORT...1 TO 2 INCH PER HOURS SNOWFALL WILL BE POSSIBLE WITH TOTAL ACCUMULATIONS UP TO 8 INCHES OVERNIGHT. THE STORM WILL BEGIN WINDING DOWN AFTER 8 AM TUESDAY MORNING. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 AM MDT TUESDAY FOR COZ033>036. WINTER WEATHER ADVISORY UNTIL 6 AM MDT TUESDAY FOR COZ030>032- 038>041. && SHORT TERM...COOPER LONG TERM....RPK AVIATION...COOPER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1106 AM MDT MON APR 22 2013 COZ030>051-231715- 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- 1106 AM MDT MON APR 22 2013 ...WINTER STORM WARNING FOR THE FRONT RANGE MOUNTAINS AND FOOTHILLS FROM NOON TODAY UNTIL 6 AM MDT TUESDAY MORNING... ..WINTER WEATHER ADVISORIES FOR THE HIGH VALLEYS AND THE WESTERN MOUNTAINS OF JACKSON AND GRAND COUNTIES AS WELL AS THE URBAN CORRIDOR FROM NOON TODAY UNTIL 6 AM TUESDAY MORNING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW WILL INCREASE FROM NORTH TO SOUTH ACROSS THE MOUNTAINS AND FRONT RANGE FOOTHILLS. STORM TOTAL ACCUMULATIONS BY LATE TONIGHT WILL RANGE FROM 7 TO 14 INCHES. COLDER TEMPERATURES AND GUSTY NORTHEAST WINDS WILL SPREAD OVER ALL OF THE NORTHEAST PLAINS THE REST OF TODAY FOLLOWING THE PASSAGE OF A FAST MOVING COLD FRONT EARLIER THIS MORNING. SNOW WILL BE DEVELOPING ALONG THE URBAN CORRIDOR AND ADJACENT PLAINS...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. STORM TOTALS WILL RANGE ANYWHERE FROM 2 TO 7 INCHES...HEAVIEST NEAR THE FOOTHILLS AND OVER THE PALMER DIVIDE. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE CHANCE OF SNOW WILL LINGER INTO TUESDAY MORNING MAINLY SOUTH OF I-70 WITH ADDITIONAL ACCUMULATIONS UP TO AN INCH. DRIER WEATHER AND WARMER TEMPERATURES ARE EXPECTED FROM WEDNESDAY THROUGH SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
819 AM MDT MON APR 22 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0800 AM SNOW 2 SSE BRECKENRIDGE 39.47N 106.03W
04/22/2013 M3.8 INCH SUMMIT CO TRAINED SPOTTER
0744 AM SNOW BLACK HAWK 39.80N 105.49W
04/22/2013 M3.2 INCH GILPIN CO TRAINED SPOTTER
1.2 INCHES SNOW PAST 45 MINUTES
0730 AM SNOW 3 N BLACK HAWK 39.84N 105.49W
04/22/2013 M4.0 INCH GILPIN CO TRAINED SPOTTER
&&
JKPRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
1030 AM MDT MON APR 22 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1020 AM SNOW 4 WNW WELLINGTON 40.72N 105.07W
04/22/2013 M1.0 INCH LARIMER CO TRAINED SPOTTER
PAST 45 MINUTES
0800 AM SNOW 2 SSE BRECKENRIDGE 39.47N 106.03W
04/22/2013 M3.8 INCH SUMMIT CO TRAINED SPOTTER
0744 AM SNOW BLACK HAWK 39.80N 105.49W
04/22/2013 M3.2 INCH GILPIN CO TRAINED SPOTTER
1.2 INCHES SNOW PAST 45 MINUTES
0730 AM SNOW 3 N BLACK HAWK 39.84N 105.49W
04/22/2013 M4.0 INCH GILPIN CO TRAINED SPOTTER
&&
JKThe national radar mosaic for the moment the first event began.
6 winter storm, 1 winter weather. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2013Every state in 2013This day in weather historyWarnings in Colorado, April 2013
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: 447337, 447338, 447339, 447340, 447341, 447342, 447344.