The second potent spring storm of the season brought very heavy snow to locations in and near the Front Range Foothills. Deep easterly upslope conditions developed east of the Continental Divide as a slow moving storm system moved across southern Colorado.
Every event with a place to put it; 4 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.
The second potent spring storm of the season brought very heavy snow to locations in and near the Front Range Foothills. Deep easterly upslope conditions developed east of the Continental Divide as a slow moving storm system moved across southern Colorado. As a result, snowfall piled up to nearly 5 feet in parts of the foothills. The heavy snow forced the closure of an 80-mile section of Interstate 70 stretching from Golden to Vail. The Red Cross opened up several shelters in Silverthorne and Frisco for stranded travelers. The interstate was closed for approximately 16 hours. Two avalanches over Berthoud Pass forced the closure of U.S. Highway 40. Two vehicles and a snow plow were caught in the second slide but no injuries were reported. The heavy snow snapped power lines in Evergreen and Nederland causing outages which affected 14,200 residents.
In the Front Range Foothills, storm totals included: 56 inches, 3 miles south of Rollinsville; 54 inches, 3 miles southeast of Pinecliffe; 48 inches near Buckhorn Mountain; 43 inches at Aspen Springs, 42 inches at Evergreen, 38 inches, 3 miles west of Conifer; 37 inches at St. Mary's Glacier, 34 inches, 4 miles east-northeast of Nederland; 33 inches at Genesee; 32 inches, 4 miles west-southwest of Evergreen. Storm totals elsewhere ranged from 1 to 2 1/2 feet.
In the North Central Mountains storm totals included: 35 inches at Bear Lake State Park, 34 inches at Lake Eldora, 28 inches near Tabernash, 25 inches at Willow Park, 23 inches at Lake Irene, 21 inches at Jones Pass. Storm totals elsewhere ranged from 10 to 20 inches.
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 16, 2:00 PM MST, 3 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 300 PM MDT THU APR 16 2009 CORRECTED ZONE NUMBER IN 1ST PARAGRAPH .SHORT TERM...COMPLEX WEATHER PATTERN SETTING UP ACROSS AREA THIS AFTERNOON. UPPER LOW SPINNING NEAR THE FOUR CORNERS SPREADING LOTS OF MOISTURE ACROSS COLORADO. SNOW HAS BEEN ONGOING ACROSS THE MOUNTAINS AND MOST OF FOOTHILLS...WITH THE SNOW LEVEL ROUGHLY AROUND 7500 FEET. THIS ELEVATION BASED MAINLY ON WEB CAMS ALONG INTERSTATE 70 THROUGH THE FOOTHILLS AND MOUNTAINS. RADAR SHOWED SOME LIGHT TO MODERATE SNOW MOVED ACROSS ZONE 37 EARLIER THIS AFTERNOON. AS FOR PLAINS...LOTS OF STRATUS ALONG FRONT RANGE WITH CONVECTIVE ELEMENTS FURTHER EAST. FIRST CONCERN IS THE THUNDERSTORMS AND SEVERE POTENTIAL ACROSS THE PLAINS EAST OF THE FRONT RANGE THROUGH THIS EVENING. THERE IS SOME GOOD CONVERGENCE JUST EAST OF THE FRONT RANGE...WITH MAINLY NORTHERLIES ALONG THE FRONT RANGE AND EAST TO SOUTHEAST FLOW FURTHER EAST. IN ADDITION...LAPS SURFACE ANALYSIS INDICATING CAPES HAVE BEEN SLOWLY INCREASING DURING THE PAST FEW HOURS...GENERALLY AVERAGING AROUND 100-200 J/KG. THERE IS A SMALL AREA OF AROUND 400 J/KG ACROSS SOUTHERN LINCOLN COUNTY. PLATTEVILLE PROFILER SHOWING EASTERLY WINDS AT THE SURFACE...SOUTHEAST ALOFT. THUS SHEAR LOOKS FAIRLY DECENT...PARTICULARLY IN THE LOWER LEVELS...WHICH SHOULD SUPPORT THUNDERSTORMS. SPC JUST ISSUED A SEVERE TSTM WATCH FOR PORTIONS OF PLAINS THROUGH 03Z. HAIL AND WIND GUSTS THE MAIN THREATS. THE SHEAR PROFILE SUPPORTS THE POTENTIAL FOR A TORNADO OR TWO. AND NOW FOR THE SNOW. BOTH THE NAM AND GFS SIMILAR IN TRACKING THE LOW ACROSS NORTHERN NEW MEXICO TONIGHT...THEN INTO SOUTHEAST COLORADO FRIDAY AFTERNOON. BOTH MODELS INDICATING ABUNDANT MOISTURE AND PRECIPITATION POTENTIAL ACROSS AREA THROUGH AT LEAST FRIDAY... MODELS ALSO SHOW GOOD QG ASCENT ACROSS AREA...THOUGH THE BEST ASCENT WILL BE ASSOCIATED WITH THE LOW. FIRST THE MOUNTAINS: LOCATION AND MOVEMENT NOT ALL THAT FAVORABLE FOR OROGRAPHICS...BUT DEEP EASTERLY FLOW DEVELOPS BY 12Z. BOTH MODELS SUGGEST A BRIEF LUL IN THE MOUNTAIN SNOWFALL DURING THE EVENING...WHICH IS NOTED IN THE MOISTURE CROSS SECTIONS. ONCE THE EASTERLIES AND MOISTURE DEEPEN... SHOULD SEE THE SNOW INCREASE AGAIN ACROSS THE HIGH COUNTRY. WILL KEEP THE WARNING GOING FOR THE MOUNTAINS...FOOTHILLS AND PARK COUNTY. HIGHEST SNOW AMOUNTS SHOULD OCCUR EAST OF THE DIVIDE. FINALLY THE PLAINS: AFTER THUNDERSTORMS THIS EVENING...SHOULD SEE PRECIPITATION BECOMING WIDESPREAD OVERNIGHT. BOTH THE NAM AND GFS BUFFER SOUNDINGS INDICATING TEMPERATURES AT OR NEAR FREEZING BY 06Z. BASED ON THIS...AM FAIRLY CONFIDENT THAT PRECIP WILL BE SNOW OVERNIGHT. SOME SUBLTE DRYING SHOWING UP IN THE MODEL CROSS SECTIONS FROM 12Z TO 18Z...THEN DEEPENS DURING THE AFTERNOON. THUS...COULD SEE SOME DECREASE IN SNOW FALL DURING THE MORNING...BEFORE INCREASING AGAIN DURING THE AFTERNOON. IN ALL...FEEL SNOW AMOUNTS SHOULD EASILY REACH WINTER STORM CRITERIA. WILL CONTINUE WITH THE CURRENT AMOUNTS IN THE SNOW GRIDS. .LONG TERM...THE UPPER LEVEL LOW WILL MOVE ALONG THE COLORADO-NEW MEXICO BORDER FRIDAY NIGHT AND END UP SOMEWHERE BETWEEN SOUTHEAST COLORADO AND THE TEXAS PAN HANDLE. DESPITE THE DIFFERENCES IN THE LOCATION OF THE 500MB LOW...MOST OF THE FORECAST AREA WILL SEE SIGNIFICANT PRECIPITATION. FOR AREAS EAST OF THE DIVIDE...THE GFS IS SHOWING 2.50 TO 4.00 INCHES OF PRECIPITATION AND THE NAM12 IS SHOWING 2.00 TO 4.00 INCHES OF PRECIPITATION FOR THE ENTIRE STORMS. EVEN THE ECMWF AND THE SREF ARE SHOWING 2-3+ INCHES OF LIQUID FROM THIS SYSTEM. SO CONFIDENCE IS HIGH IN SEEING SIGNIFICANT MOISTURE. EAST TO NORTHEAST 700MB WINDS OF 20 KNOTS WILL CONTINUE TO TRANSPORT AMPLE MOISTURE INTO THE AREA FRIDAY NIGHT. HAVE INCREASED POPS TO 100 PERCENT FOR MOST OF THE AREA AND MENTIONED HEAVY SNOW FOR AREAS EAST THE CONTINENTAL DIVIDE FRIDAY NIGHT. STILL LOOKS LIKE THE RAIN SNOW LINE WILL BE OVER THE EASTERN PLAINS. AS THE LOW PROGRESSES EAST...WINDS WILL SLOWLY BACK TO THE NORTHWEST...A DOWNSLOPE DIRECTION FOR THE URBAN CORRIDOR. PRECIPITATION WILL DECREASE ONCE WINDS TURN NORTHWESTERLY DURING THE DAY SATURDAY. MODELS STILL INDICATE SOME LIGHT PRECIPITATION FOR MOST OF THE AREA SATURDAY WITH A STRONGER BAND SETTING UP EAST OF I-25. PRECIPITATION WILL CONTINUE TO DECREASE AND COME TO AN END SATURDAY NIGHT AS THE UPPER LEVEL LOW CONTINUES TO MOVE EAST. NORTHWEST FLOW ALOFT WILL BE OVER THE REGION COME SUNDAY WITH THE UPPER LEVEL LOW EAST OF THE AREA AND AN UPPER LEVEL RIDGE BUILDING OVER THE WESTERN U.S. LOWERED HIGH TEMPERATURES OVER THE WESTERN HALF OF THE FORECAST BECAUSE OF THE EXPECTED SNOW COVER. KEPT HIGH TEMPERATURES AS IS OVER THE EASTERN PLAINS. THE DRY CONDITIONS AND WARMING TREND WILL CONTINUE INTO NEXT WEEK AS THE UPPER LEVEL RIDGE MOVES OVER THE CENTRAL ROCKIES. DID LOWER TEMPERATURES A LITTLE MONDAY OVER THE EXPECTED SNOW COVERED AREAS. THE RIDGE WILL FLATTEN SOME TUESDAY THROUGH THURSDAY BUT THE REGION WILL STILL FEEL THE AFFECTS OF IT WITH WARM AND DRY CONDITIONS PREVAILING. WENT WITH HIGHS IN THE UPPER 60S TO MID 70S FROM TUESDAY TO THURSDAY FOR THE URBAN CORRIDOR AND EASTERN PLAINS. && .AVIATION...EXPECT IFR CEILINGS TONIGHT...CONTINUING THROUGH FRIDAY. SHOWERS WILL BE ON THE INCREASE DURING THE EVENING...WHICH WILL BE INITIALLY MIXED WITH SNOW. THE PRECIPITATION WILL BE IN THE FORM OF SNOW AFTER MIDNIGHT. MVFR VISIBILITIES TO OCCUR WITH THE PASSING SHOWERS THIS EVENING...THEN BECOME WIDESPREAD AFTER MIDNIGHT WITH PERIODS OF IFR CONDITIONS. THERE COULD BE A BREAK IN THE SNOW BETWEEN 12Z AND 18Z AS SLIGHTLY DRIER AIR MOVES IN THE AREA. BUT THE SNOW SHOULD INCREASE AGAIN BY 18Z. && .BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING THROUGH MID DAY SATURDAY FOR ZONES 33>37...41... ...WINTER STORM WARNING FROM TONIGHT AT MIDNIGHT THROUGH MID DAY SATURDAY FOR ZONES 38>40...43... D-L/MEIER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1051 AM MDT THU APR 16 2009 COZ030>051-171200- 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- 1051 AM MDT THU APR 16 2009 ...WINTER STORM WARNING THIS AFTERNOON THROUGH NOON SATURDAY FOR THE MOUNTAINS...FOOTHILLS AND PARK COUNTY... ...WINTER STORM WARNING THIS EVENING THROUGH NOON SATURDAY FOR THE PALMER DIVIDE... ...WINTER STORM WARNING FOR THE FRONT RANGE URBAN CORRIDOR FROM MIDNIGHT TONIGHT TO NOON SATURDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW WILL CONTINUE ACROSS THE MOUNTAINS...FOOTHILLS AND PARK COUNTY THROUGH TONIGHT...AND WILL BE HEAVY AT TIMES. THE SNOW LEVEL WILL INITIALLY BE AROUND 8000 FEET...BUT WILL LOWER BY THE EVENING. ACROSS THE PLAINS...RAIN SHOWERS WILL DEVELOP DURING THE AFTERNOON... BECOMING WIDESPREAD DURING THE EVENING AND CONTINUING OVERNIGHT. THE RAIN WILL MIX WITH SOME SNOW DURING THE EVENING...THEN CHANGE TO ALL SNOW LATER TONIGHT. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE THIS AFTERNOON AND EVENING. ONE OR TWO SEVERE THUNDERSTORMS EAST OF A STERLING TO LIMON LINE COULD BECOME SEVERE. THE MAIN THREAT WILL BE WIND GUSTS TO AROUND 60 MPH BUT HAIL AROUND AN INCH IN DIAMETER AND AN ISOLATED TORNADO ARE ALSO POSSIBLE. A VERY MOIST SPRING STORM SYSTEM WILL MOVE ACROSS COLORADO TONIGHT THROUGH SATURDAY WHICH WILL AFFECT THE AREA. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY WIDESPREAD PRECIPITATION IS EXPECTED FRIDAY AND SATURDAY. SNOW WILL BE HEAVY IN THE MOUNTAINS EAST OF THE DIVIDE...THE FOOTHILLS...SOUTH PARK...AND PALMER RIDGE...AND POSSIBLY OVER THE URBAN CORRIDOR. SNOW ACCUMULATIONS IN THE MOUNTAINS AND FOOTHILLS WILL RANGE FROM 18 TO 36 INCHES. THE PALMER RIDGE WILL SEE 12 TO 24 INCHES...WITH 8 TO 16 INCHES IN SOUTH PARK. OVER THE PLAINS...A SNOW RAIN MIX WILL CHANGE OVER TO ALL SNOW FRIDAY. THE FAR EASTERN PLAINS WILL SEE MORE RAIN THAN SNOW. ACCUMULATIONS OVER THE URBAN CORRIDOR WILL RANGE FROM 10 TO 24 INCHES...WITH LESSER AMOUNTS HEADING EASTWARD INTO THE PLAINS. SNOW WILL DIMINISH SATURDAY AFTERNOON AND EVENING. BY SUNDAY...CONTINUING THROUGH MID NEXT WEEK...AN UPPER RIDGE OF HIGH PRESSURE WILL BRING DRY CONDITIONS TO ALL THE FORECAST AREA. TEMPERATURES WILL WARM TO ABOVE SEASONAL NORMALS FOR MONDAY THROUGH WEDNESDAY ACROSS ALL THE FORECAST AREA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY...BUT REPORTS OF SNOWFALL DURING THE UPCOMING STORM WILL BE APPRECIATED. D-L/MEIER
The national radar mosaic for the moment the first event began.
4 winter storm. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2009Every state in 2009This day in weather historyWarnings in Colorado, April 2009
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: 157000, 157001, 157002, 157003.