A strong upper level jetstream moved over northern Colorado and produced bands of very heavy snow. The heaviest snowfall was concentrated along and north of the Interstate 70 Corridor and extended from the mountains and high valleys to the Urban Corridor and northeast plains of Colorado.
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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 strong upper level jetstream moved over northern Colorado and produced bands of very heavy snow. The heaviest snowfall was concentrated along and north of the Interstate 70 Corridor and extended from the mountains and high valleys to the Urban Corridor and northeast plains of Colorado. The snow fell at a rate of 2 to 3 inches per hour during the late afternoon and evening hours of the 15th and forced the cancellation of 25 flights at Denver International Airport. Interstate 25 was closed in both directions between Wellington and Cheyenne due to snow and blowing snow.
In the mountain, high valley and foothill locations storm totals included: 21 inches near Estes Park; 18 inches at Bear Lake; 17 inches at Willow Park; 16 inches near Ward; 15.5 inches at Genesee; 15 inches at Grand Lake and near Nederland; 14.5 inches near Idaho Springs; 14 inches near Idledale; 13.5 inches in Bergen Park; 13 inches near Allenspark, Blackhawk, Conifer and 6 miles northwest of Lyons; 11.5 inches near Silverthorne.
Across the Urban Corridor and northeast plains, storm totals included: 16.5 inches, 5 miles east of Boulder; 16 inches, 5 miles northeast of Westminster; 15.5 inches in Lafayette; 15 inches in Frederick and Louisville; 14.5 inches in Broomfield; 13.5 inches at the National Weather Service Office in Boulder; 13 inches, 5 miles west-northwest of Brighton; 12.5 inches in Wheat Ridge; 12 inches near Arvada and Greeley; 11.5 inches near Loveland; 10 inches near Commerce City, Northglenn and Superior; 9 inches near Thornton; 7.5 inches at Denver International Airport; 7 inches near Crook; with 6 inches near Fort Collins and Fort Morgan.
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 15, 2:42 AM MST, 18 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 342 AM MDT MON APR 15 2013 .SHORT TERM...MAIN CHALLENGE TODAY AND TONIGHT WILL BE SNOWFALL POTENTIAL IN THE MOUNTAINS AND PORTIONS OF THE NORTHEAST PLAINS. NO EASY CHALLENGE AT THAT...AS ANOTHER STRONG 110KT JET CORE MEANDERS ACROSS CENTRAL AND NORTHERN COLORADO THROUGH TONIGHT. WITH THE JET...CSI BANDED SNOWFALL WILL OCCUR...BUT AS WITH THESE TYPE OF EVENTS THE QUESTION IS WHERE THE HEAVIER SNOWFALL WILL OCCUR? GIVEN CURRENT RADAR AND OBSERVATIONS...PRECIP HAS BEEN TRYING TO DEVELOP OVER THE PAST SEVERAL HOURS WITH A CONCENTRATION OF SNOW ALONG AND JUST SOUTH OF THE WYOMING BORDER. DRIER LOW LEVELS IS MAKING THIS PRECIP PROCESS TAKE A BIT LONGER ON THE ADJACENT PLAINS. A BROADER AREA OF SNOW SHOULD BE MOVING INTO THE MOUNTAINS BEFORE DAYBREAK GIVEN TRENDS ON GJT RADAR. MODELS CONTINUE TO FOCUS THE HEAVIEST SNOWFALL NORTH OF THE INTERSTATE 70 CORRIDOR AND ESPECIALLY LOCATIONS FURTHER NORTH TOWARDS THE WYOMING BORDER. THE GFS HAS THE BAND OF SNOW A BIT FURTHER SOUTH...MORE OVER I-70 CORRIDOR AND INCLUDING SUMMIT COUNTY. FOR NOW WILL UPGRADE THE WATCH TO WARNINGS FOR ZONE 31..33..35..38..42 AS THIS IS THE HIGHER CONFIDENCE OF SNOWFALL POTENTIAL. ZONE 34 IS IFFY AND COULD BE ON THE EDGE OF THE HEAVIER SNOWFALL. GIVEN UNFAVORABLE OROGRAPHICS WILL START WITH AN ADVISORY THERE FOR NOW. HILITES FOR LOWER ELEVATIONS IS EVEN MORE TRICKY...ESPECIALLY LOCATIONS FROM BOULDER TO GREELEY. CERTAINLY SOME BANDED SNOWFALL IS LIKELY BUT WOULD BE RATHER LOCALIZED AND FEEL MOST OF THE SNOW WOULD MELT ON PAVEMENT AS TEMPERATURES IN THE BOULDER/DENVER AREA WILL BE IN THE UPPER 30S/LOWER 40S. THIS COULD END UP BEING A LOW IMPACT EVENT FOR THE MAJORITY OF THOSE AREAS AND WILL KEEP THIS AS A WATCH FOR NOW. DENVER IS RIGHT ON THE EDGE BUT FEEL MAJORITY OF THE SNOW TODAY WILL BE NORTH OF DENVER. LOCATIONS SOUTH OF DENVER INCLUDING THE PALMER DIVIDE WILL BE THE DRIEST WITH STRONG SOUTH TO SOUTHEAST LOW LEVEL FLOW. THERE SHOULD BE A BETTER CHANCE OF SNOW TONIGHT ACROSS MUCH OF THE PLAINS AS COLDER AIR USHES IN FROM THE NORTH AS LOW LEVEL FLOW SHIFTS NORTH AND NORTHEAST. .LONG TERM...THE UPPER LEVEL TROUGH WILL CONTINUE OVER THE GREAT BASIN ON TUE WITH SSWLY FLOW ALOFT. MEANWHILE SFC LOW PRES WILL REMAIN OVER WRN CO WITH SELY LOW LVL FLOW EAST OF THE MTNS. CROSS-SECTIONS SHOW UPPER LEVEL JET WILL LIFT NORTH ON TUE WITH DECREASING MOISTURE IN THE MID LEVELS WITH RATHER STABLE LAPSE RATES. THERE WILL STILL BE SOME SNOW IN THE MTNS WITH THE BEST CHC OVER ZNS 31 AND 33 HOWEVER AMOUNTS SHOLD GENERALLY BE ON THE LIGHT SIDE. EAST OF THE MTNS SOME LIGHT SNOW MAY LINGER EARLY IN THE MORNING HOURS FM DENVER NORTH TO THE WY BORDER BUT SHOULD GRADUALLY DECREASE BY MID TO LATE MORNING. BY AFTN WITH SELY LOW LVL FLOW APPEARS BEST CHC OF ANY ADDITIONAL PCPN WILL BE IN THE NRN FOOTHILLS AND ADJACENT PLAINS NR THE WYOMING BORDER WITH DECREASING CHANCES FURTHER SOUTH. MEANWHILE WITH SELY LOW LVL FLOW WILL LIKELY SEE A DENVER CYCLONE DVLP WHICH WILL MAKE FOR AN INTERESTING TEMP FCST. HIGHS FM DENVER SE TOWARDS LIMON COULD RISE INTO THE MID 40S TO NEAR 50 AS SOME CLEARING OCCURS WHILE AREAS TO THE N AND NW OF THE DENVER CYCLONE UP TO THE WYOMING BORDER STAY IN THE 30S WITH CONSIDERABLE CLOUD COVER. FOR TUE NIGHT INTO WED THE UPPER LEVEL TROUGH OVER THE GREAT BASIN WILL BEGIN TO SLOWLY MOVE EASTWARD. AT THIS POINT THERE IS CONSIDERABLE DISAGREEMENT AMONG THE MODELS WHETHER IT WILL REMAIN AN OPEN TROUGH OR EVOLVE INTO A CLOSED SYSTEM. THE GFS AND ECMWF KEEP AN OPEN TROUGH WHILE THE NAM AND GEM HAVE A MORE CLOSED SYSTEM. DESPITE THEIR DIFFERENCES ALL OF THE MODELS SHOW SOME INCREASE IN MID LVL QG ASCENT TUE NIGHT THRU WED ALONG WITH IMPROVING LAPSE RATES HOWEVER THERE ARE DIFFERENCES IN THE AMOUNT OF MID LVL MOISTURE. THE NAM AND TO SOME EXTENT THE GFS KEEP THE DEPER MOISTURE OVER WYOMING TUE NIGHT INTO INTO WED MORNING WHILE THE ECMWF AND GEM HAVE SOMEWHAT DEEPER MOISTURE. MEANWHILE AT THE SFC THE NAM AND GFS KEEP A SFC LOW CENTERED NR DENVER ON TUE NIGHT INTO WED MORNING WHILE THE GEM AND ECMWF HAVE A SURGE OF COOLER AIR MOVING INTO NERN CO TUE NIGHT INTO WED MORNING. AS A RESULT THE ECMWF AND GEM WOULD HAVE A BETTER CHC OF SNOW DEVELOPING LATE TUE NIGHT INTO WED MORNING VS THE NAM AND GFS WHICH KEEP THE BEST CHC OVER WYOMING. AT THIS POINT ITS NOT CLEAR WHICH SOLUTIONS ARE THE BEST FM TUE NIGHT INTO WED MORNING SO WILL NOT ALTER PREVIOUS FCST TOO MUCH. BY WED AFTN AND NIGHT THE MAIN PART OF THE UPPER LEVEL TROUGH IS FCST TO MOVE ACROSS THE AREA IN ONE FORM OR ANOTHER. THE NAM HAS A CLOSED LOW OVER WY BY WED EVENING WHILE THE GEM HAS IT OVER SRN COLORADO. MEANWHILE AS MENTIONED ABV THE ECMWF AND GFS HAVE AN OPEN TROUGH MOVING ACROSS. BY WED AFTN ALL OF THE MODELS HAVE THE LOW LVL FLOW MORE NNE WITH DECENT MOISTURE EXCEPT FOR THE NAM. IN ADDITION THERE IS DECENT MID LVL QG ASCENT AND FAVORABLE LAPSE RATES SO ONE WOULD THINK THERE WILL BE A GOOD CHC OF SNOW WED AFTN INTO EARLY WED EVENING ACROSS NERN CO. IN THE MTNS THERE SHOULD BE A BETTER CHC OF SNOW AS WELL ALTHOUGH THE OROGRAPHICS ARE PRETTY WEAK. AS FOR HIGHS ON WED WILL KEEP READINGS IN THE LOWER TO MID 30S FOR NOW ACROSS NERN CO ALTHOUGH IT COULD BE COLDER IF THE ECMWF AND GEM END UP BEING RIGHT. BY THU THE MAIN UPPER LEVEL TROUGH SHOULD MOVE EAST OF THE AREA WITH DRIER NWLY FLOW ALOFT DEVELOPING. THERE WILL STILL BE ENOUGH LOW LVL MOISTURE IN THE MTNS FOR SOME -SHSN HOWEVER IT SHOULD BY DRY ELSEWHERE ALTHOUGH THERE WILL BE GUSTY NWLY WINDS OVER THE PLAINS. WILL KEEP HIGHS IN THE 35 TO 40 DEGREE RANGE OVER NERN CO. FOR FRI RATHER DRY NWLY FLOW ALOFT WILL REMAIN OVER THE AREA WITH SOME MODERATION IN THE 850-700 MB TEMPS SO SHOULD SEE HIGHS REACH THE UPPER 40S TO LOWER 50S OVER NERN CO. ON SAT A DISTURBANCE IN NW FLOW ALOFT WILL AFFECT THE AREA AND BRING A CHC OF SNOW TO THE MTNS. ACROSS NERN CO A WEAK FNT MAY MOVE INTO NERN CO IN THE AFTN AND AS THE DISTURBANCE MOVES ACROSS THERE COULD BE A SLIGHT CHC OF SHOWERS. && .AVIATION...HIGH STRATUS DECK IN PLACE AT LOCAL TERMINALS WITH ILS APPROACHES LIKELY AT DENVER FOR MAJORITY OF TODAY AND TONIGHT. GIVEN THE MODEST SOUTH TO SOUTHEAST WINDS THIS AM...SNOW DEVELOPMENT WILL BE SPARSE WITH ONLY SCATTERED SHOWERS AND RUNWAY SURFACES AT LEAST JUST REMAINING WET FOR TODAY. BEST CHANCE OF SNOW AND IFR CONDITIONS WILL BE TONIGHT AS SURFACE LOW PRESSURE INTENSIFIES AND DRAGS COLDER IN FROM THE NORTH WITH NORTH TO NORTHEAST LOW LEVEL FLOW. SNOW ACCUMULATIONS BY TUE AM LIKELY TO RANGE FROM 2 TO 4 INCHES WITH MOST OF THE SNOWFALL TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MDT TUESDAY FOR COZ030-032- 034. WINTER STORM WARNING UNTIL 6 AM MDT TUESDAY FOR COZ031-033-035- 038-042. WINTER STORM WATCH THROUGH LATE TONIGHT FOR COZ039-043-044. && SHORT TERM...ENTREKIN LONG TERM....RPK AVIATION...ENTREKIN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1110 AM MDT SUN APR 14 2013 COZ030>051-151715- 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- 1110 AM MDT SUN APR 14 2013 ...WINTER STORM WATCH MONDAY THROUGH LATE MONDAY NIGHT FOR THE NORTHERN MOUNTAINS AND NORTHERN FOOTHILLS... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW SHOWERS OVER THE MOUNTAINS WILL GRADUALLY DECREASE THROUGH THE AFTERNOON. ADDITIONAL SNOWFALL WILL BE INCHES OR LESS...MAINLY ON WEST FACING SLOPES. GUSTY WEST WINDS WILL RESULT IN SOME BLOWING SNOW AT TIMES. WINDS ACROSS THE PLAINS WILL BE STRONG THROUGH THE AFTERNOON WITH GUSTS OF 35 TO 50 MPH AT TIMES. TEMPERATURES WILL BE COOLER TODAY WITH READINGS IN THE 50S...IN SPITE OF SUNNY SKIES. LIGHT SNOW WILL REDEVELOP LATER TONIGHT OVER THE MOUNTAINS WITH 1 TO 3 INCHES OF ACCUMULATION BY MONDAY MORNING. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A STORM SYSTEM WILL MOVE INTO THE GREAT BASIN ON MONDAY WITH MOIST SOUTHWEST FLOW ALOFT. IN ADDITION A COLD FRONT WILL MOVE INTO NORTHEAST COLORADO WITH UPSLOPE FLOW DEVELOPING ALONG THE FRONT RANGE. THERE WILL BE A THREAT FOR HEAVY SNOW IN THE NORTHERN MOUNTAINS AND ACROSS THE NORTHERN FOOTHILLS FROM MONDAY THROUGH MONDAY NIGHT. IN ADDITION THERE WILL BE SOME POTENTIAL FOR HEAVY SNOW MONDAY NIGHT IN THE FORT COLLINS AND GREELEY AREAS AND POSSIBLY ACROSS THE NORTHERN SUBURBS OF DENVER. SNOW ACCUMULATIONS OF 8 TO 16 INCHES WILL BE POSSIBLE IN THE NORTHERN MOUNTAINS AND NORTHERN FOOTHILLS. AT LOWER ELEVATIONS FROM 3 TO 6 INCHES COULD FALL MONDAY NIGHT FROM NORTH OF DENVER TO THE WYOMING BORDER WITH HIGHER AMOUNTS POSSIBLE. ON TUESDAY LIGHT SNOW WILL BE POSSIBLE IN MOST AREAS BEFORE THE MAIN STORM SYSTEM MOVES ACROSS LATE TUESDAY INTO WEDNESDAY. ANOTHER ROUND OF HEAVIER SNOW COULD OCCUR IN THE MOUNTAINS... FOOTHILLS AND ADJACENT PLAINS ON WEDNESDAY AS A SECOND SURGE OF COLDER AIR ENHANCES UPSLOPE FLOW ACROSS NORTHERN COLORADO. FAIRLY MOIST NORTHWESTERLY FLOW ALOFT WILL MOVE INTO THE FORECAST AREA THURSDAY THROUGH NEXT WEEKEND. THERE WILL BE A CHANCE OF SNOW IN THE MOUNTIANS WITH TEMPERATURES REMAINING BELOW SEASONAL NORMALS. BY THURSDAY...THE STORM SYSTEM SHOULD EXIT THE REGION WITH ONLY A CHANCE OF LIGHT SNOW IN THE MOUNTAINS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.
The national radar mosaic for the moment the first event began.
12 winter storm. 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: 447302, 447303, 447305, 447307, 447311, 447308, 447309, 447312, 447313, 447310, 447304, 447306.