Heavy snow developed across the Front Range Foothills as the first of two storm systems moved through Colorado. Snowfall totals included 9 inches at Allenspark, with 8 inches at Hourglass Lake and 5 miles east of Nederland.
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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.
Heavy snow developed across the Front Range Foothills as the first of two storm systems moved through Colorado. Snowfall totals included 9 inches at Allenspark, with 8 inches at Hourglass Lake and 5 miles east of Nederland.
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 21, 1:40 PM MST, 4 hours 20 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 240 PM MDT WED APR 21 2004 .SHORT TERM...ONE-TWO PUNCH OF WEATHER HEADING OUR WAY. THE FIRST SYSTEM IS WEAK AND WILL BE MOVING ACROSS THE CWA THIS AFTERNOON AND EVENING. RADAR ECHOES LOOK MORE LIKE SUMMER WITH CONVEGENCE LINE DEVELOPING EAST DENVER. IN ANY EVENT...THIS SYSTEM DOES ALLOW FOR SOME WEAK QG ASCENT TO CONTINUE OVER THE CWFA THROUGH THIS EVENING. SOME MID LEVEL INSTBY AS WELL WITH WEAK UPSLOPE BLO 700 MB. SNOW NUMBERS...BARRING ANY SIGNIFICANT CONVECTION...SHOULD BE BLO ADVSY CRITERIA SO WILL HOLD OFF ON ISSUING A HIGHLIGHT TONIGHT. SWING SHIFT HOWEVER WILL NEED TO KEEP A CLOSE EYE ON THIS. AS FOR THE NORTHEASTERN PLAINS...THE MESOETA DEVELOPED SIGNIFICANT MOISTURE AROUND AKRON...BUT WET BULB FROM ETA BUFFER SOUNDINGS SHOULD BE TOO HIGH FOR SNOW...SO WILL GO WITH JUST RAIN THERE. A SECOND AND MUCH MORE POTENT SYSTEM IS PROGGED BY ALL THE MODELS TO DROP INTO THE FOUR CORNERS AREA BY 00Z THURSDAY. THIS WILL ALLOW FOR A DEEP ELY UPSLOPE COMPONENT TO DEVELOP BY 00Z THURSDAY. SNOW WILL INITIATE SOONER IN THE MOUNTAINS AND FOOTHILLS SO WILL GO A WINTER STORM WATCH STARTING THURSDAY AFTERNOON. WILL ALSO ADD IN ZONE 41 FOR THOSE AREAS ABOVE 6000 FEET AS A PRECAUTION. QG ASCENT ASSOCIATED WITH THIS SYSTEM WILL INCREASE OVER OUR CWFA IN THE AFTERNOON. THERE SHOULD BE A GOOD WINDOW OF DYANAMICS...INTBY AND UPSLOPE FOR LATE THURSDAY AFTERNOON AND THURSDAY EVENING. .LONG TERM DISCUSSION...THU NGT-SAT...ETA HAS COME INTO GUD AGREEMENT WITH THE AVN IN FORMING CLOSED UPR LO NR 4 CORNERS BY 00Z FRI. SYS WILL LINGER OVR AREA THRU FRI NGT. SFC LO PRES CNTR WILL FORM WELL TO S OF FCST AREA WITH RESULTANT DEEP N TO ELY FLO ALF AGAINST ERN SLPS. MDLS SUGGEST ANYWHERE FM 20 TO 30 INCHES OF SNW OVR FAVORED HIR TRRN TO SW AND S OF DEN WITH ONLY A FEW INCHES NR THE NRN BRDR AND NERN CORNER. E SLP OF MTNS AND ERN FTHLLS SHUD RECEIVE HVY AMTS OF SNW ALG WITH PALMER DVD. MST OF SNW SHUD OCCUR THU NGT DUE TO NIGHTTIME COOLING WITH LESSER AMTS ON FRI. SNW ON FRI MAY BE MIXED WITH RAIN AT TIMES ON NERN PLAINS. THERE WILL BE STG DYNAMICS WITH SYS IN FORM OF PVA AND UPWARD Q-G FORCING. SAT SHUD TURN DRY AND WARMER AS SYS SLOWLY EXITS AREA. WILL GENERALLY UNDERCUT MOS TEMP GUIDANCE THRU THE PERIOD. SNW CVR MAY INHIBIT WARMING ON SAT. IN THE EXTENDED PERIOD...SUN-WED...AN UPR RDG WILL BUILD OVR WRN U.S. AND SPREAD OVR CNTRL RCKYS THRU PRD. THE AIR MASS WILL REMAIN MSTLY DRY AND STBL AS TEMPS WARM TO NEAR AND ABV SEASONAL NORMS. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH MTNS...ERN FTHLLS AND PALMER DVD FROM THU AFTN THRU FRI...ZNS 33..34..35..36..37..41. WINTER STORM WATCH NERN PLAINS THU NGT AND FRI...ZNS 38..39..40.. 43..44..45..46..47..49. COOPER/GARD...WFO BOULDER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1058 AM MDT WED APR 21 2004 COZ030>051-221200- 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- 1058 AM MDT WED APR 21 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW SHOWERS WILL OCCUR IN THE MOUNTAINS TODAY THROUGH THIS EVENING WITH ACCUMULATIONS GENERALLY IN THE 2 TO 4 INCH RANGE ALTHOUGH A FEW SPOTS MAY GET UP TO 6 INCHES. OVER LOWER ELEVATIONS SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND CONTINUE INTO THE EVENING HOURS. MOISTURE WILL INCREASE ACROSS THE AREA THROUGH TONIGHT AND COMBINED WITH A SERIES OF WEAK DISTURBANCES MOVING ACROSS WILL ALLOW FOR THE PRECIPITATION TO DEVELOP. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY A SIGNIFICANT SPRING STORM WILL BRING PRECIPITATION TO ALL OF THE FORECAST AREA FROM THURSDAY THROUGH FRIDAY EVENING. THE FOOTHILLS AND PALMER DIVIDE COULD SEE SUBSTANTIAL SNOWFALL AMOUNTS BY FRIDAY AFTERNOON. DRY CONDITIONS WILL RETURN TO THE AREA ON SATURDAY WITH A SLIGHT CHANCE OF SHOWERS ON SUNDAY. DRY AND WARMER WEATHER CONDITIONS ARE EXPECTED ON MONDAY AND TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. COOPER/GARD...WFO BOULDER
The national radar mosaic for the moment the first event began.
1 winter storm. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2004Every state in 2004This day in weather historyWarnings in Colorado, April 2004
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: 5390728.