A winter storm brought heavy snow to the foothills of Douglas, Jefferson and Park Counties. 5 inches at Roxborough State Park; 10 inches, 3 miles east-southeast of Tiny Town.
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.
A winter storm brought heavy snow to the foothills of Douglas, Jefferson and Park Counties. Storm totals included: 19 inches, 3 miles west-southwest of Conifer; 17.5 inches, 4 miles south-southeast of Pinecliffe; 14 inches, 5 miles east-southeast of Aspen Park; 12.5 inches, 7 miles southwest of Boulder and at Genesee; 12 inches at Strontia Springs Dam, 10.5 inches at Roxborough State Park; 10 inches, 3 miles east-southeast of Tiny Town.
Heavy snow also occurred across the western and southern Denver suburbs and Palmer Divide. Storm totals included: 9 inches, near Louviers and 3 miles south-southeast of Morrison; 8 inches at Ralston Reservoir; 7 inches in Lakewood; 6.5 inches, 2 miles southeast of Highlands Ranch; 6 inches in Englewood and 5 miles south-southeast of Sedalia.
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 Feb 4, 9:14 PM MST, 6 hours 46 minutes earlier.
FXUS65 KBOU 050414 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 914 PM MST FRI FEB 4 2011 .UPDATE...CURRENT SATELLITE AND RADAR PICTURES ARE INDICATING THE SNOW SHOWERS OVER THE PLAINS HAVE ENDED WHILE SNOW SEEMS TO BE SLIGHTLY INCREASING OVER THE HIGH MOUNTAINS. CDOT CAMERAS ALSO SHOW THIS. CURRENT HIGHLIGHTS IN THE MOUNTAINS LOOK OK FOR NOT. SO WILL REMOVE POPS FOR PLAINS. && .PREV DISCUSSION... /ISSUED 315 PM MST FRI FEB 04 2011/ SHORT TERM...STRANGE PATTERN THE PAST COUPLE DAYS WITH WARM ADVECTION IN PLACE BUT STILL SOME PRECIPITATION ON THE PLAINS. TODAYS PRECIPITATION HAS BEEN MUCH LIGHTER WITH A LOT OF SUBCLOUD EVAPORATION AND MORE NORTHERLY...VERSUS NORTH/NORTHEASTERLY...FLOW YESTERDAY. THE LOCAL PROFILERS ARE SHIFTING SLIGHTLY WEST OF DUE NORTH THIS AFTERNOON...SO PRECIPITATION AREA SHOULD BE SHIFTING EASTWARD THROUGH THE COURSE OF THE EVENING AS DOWNSLOPE WORKS OFF THE FOOTHILLS. LOW LEVELS HAVE MOISTENED SOMEWHAT THIS AFTERNOON WITH LESS SUBCLOUD COOLING AND TEMPERATURES HAVE RISEN ENOUGH TO MENTION SOME RAIN/SNOW MIX IN ELEVATIONS BELOW ABOUT 5500 FEET. IN THE MOUNTAINS...CAMS AND SNOTEL OBS SHOW SOME LIGHT SNOW AND ACCUMULATIONS...AND THE LIGHT SHOWERS WILL CONTINUE INTO THE EVENING WITH PERSISTENT WEST/NORTHWEST FLOW AND MOISTURE IN PLACE. SNOW INTENSITY IS EXPECTED TO PICK UP AS EARLY AS MIDNIGHT IN ZONE 31 WHERE BETTER MOISTURE AND LAPSE RATES FIRST ARRIVE...AND THEN IN ZONES 33 AND 34 BEFORE DAYBREAK SATURDAY. THIS DEEP MOISTURE AND INSTABILITY WILL COINCIDE WITH ARRIVAL OF THE NEXT SHORT WAVE AND INCREASING Q-G LIFT. IN ADDITION...WE HAVE THE FAVORED NORTHWEST FLOW. LOCAL SNOW MODEL SUGGESTS 2-5 TONIGHT AND 5-10 INCHES SATURDAY IN ZONE 31...AND 1-2 TONIGHT AND 3-6 INCHES SATURDAY IN THE FRONT RANGE MOUNTAINS ZONES 33 AND 34. THESE AMOUNTS WOULD WARRANT A WARNING IN ZONE 31...AND AN ADVISORY FOR THE FRONT RANGE MOUNTAINS AND SUMMIT COUNTY. THESE NUMBERS COULD EVEN BE A LITTLE LOW GIVEN THE SYNOPTIC SCALE LIFT NOTED IN THE FRONT LEFT EXIT REGION OF THE APPROACHING 130 KNOT JET. ON THE PLAINS....EXPECT FRONTAL PASSAGE AROUND NOON SATURDAY WITH GUSTY NORTH WINDS AND FALLING TEMPERATURES BEHIND THE FRONT THROUGH THE AFTERNOON. MOST MODEL DATA SHOWS WINDS TURNING DUE NORTHERLY WITH POSSIBLY SOME SHALLOW NORTH/NORTHEAST TOWARD THE SURFACE. WITH THE SYNOPTIC SCALE Q-G LIFT NOTED...A VERY UNSTABLE AIRMASS...AND POTENTIAL FOR AT LEAST SHALLOW UPSLOPE...WE HAVE INCREASED THE POPS IN/NEAR THE FOOTHILLS INCLUDING THE I-25 CORRIDOR WHERE ACCUMULATING SNOW WOULD BE POSSIBLE IF WINDS TURN INTO THE FOOTHILLS. LONG TERM...MODELS ARE BEGINNING TO HAVE SOME AGREEMENT ON THE FORECAST FOR NEXT WEEK...BUT STILL A CHALLENGING FORECAST WITH THE NORTHWEST FLOW PATTERN ALOFT. THE SNOW WILL BE TRENDING LIGHTER OVER THE MOUNTAINS SATURDAY NIGHT AS MOISTURE AND LAPSE RATES DECREASE AND DOWNWARD QG VERTICAL MOTION SLIDES OVER THE AREA. THE JET WILL ALSO STILL MOVE CLOSER WITH INCREASING SPEEDS...MOST LIKELY OFFSETTING SOME OF THE NEGATIVE EFFECTS. 2 TO 4 INCHES ARE EXPECTED OVER THE HIGHER MOUNTAINS SATURDAY NIGHT ALTHOUGH SOME BANDING MAY OCCUR TO BRING LOCALLY HIGHER AMOUNTS. OVER THE PLAINS...THE SNOW WILL BE DIMINISHING BEHIND THE FRONT. SNOW WILL LIKELY CONTINUE OVER THE PALMER DIVIDE HOWEVER MOUNTAIN TOP FLOW WILL BE TURNING MORE OF A DOWNSLOPING DIRECTION AFTER MIDNIGHT SO THERE WILL STILL BE A SLIGHT CHANCE FOR SNOW OVER THE REST OF THE PLAINS AS THE JET MOVES CLOSER. LAPSE RATES WILL CONTINUE TO DECREASE SUNDAY TO DECREASE THE SNOW FALL OVER THE MOUNTAINS...BUT STILL EXPECT ABOUT 1.5 TO 3 INCHES ACCUMULATION DURING THE DAY AS OROGRAPHICS AND MOISTURE REMAIN. OVER THE PLAINS TEMPERATURES WILL BE ABOUT 10 DEGREES COOLER IN THE POST FRONTAL AIRMASS WITH A SLIGHT CHANCE OF SNOW REMAINING AS THE JET MOVES OVER HEAD. A SURFACE LOW WILL START DEEPENING ON THE LEE SIDE OF THE NORTHERN ROCKIES SUNDAY NIGHT AND DROP SOUTH. AT THE SAME TIME...MOISTURE WILL BE INCREASING AND WEST WINDS WILL BE PICKING UP DUE TO THE INCREASING PRESSURE GRADIENT. SNOW INTENSITY WILL PICK UP OVER THE MOUNTAINS WITH NEAR ADVISORY AMOUNTS WITH AREAS OF BLOWING SNOW DUE TO THE WINDS AROUND 35 TO 45 MPH WITH GUSTS TO 65 MPH. LOOK FOR DOWNSLOPING CONDITIONS OVER THE PLAINS TO MODERATE MINIMUM TEMPERATURES TO ABOVE NORMAL. THE SURFACE LOW WILL CONTINUE TO SLIDE SOUTH INTO THE STATE MONDAY CONTINUING THE WARM ADVECTION AND DOWNSLOPING CONDITIONS AHEAD OF THE NEXT SYSTEM. MODELS HAVE SLOWED THE NEXT SYSTEM AND ASSOCIATED ARCTIC COLD FRONT...SO HAVE INCREASED TEMPERATURES MONDAY INTO THE 40S OVER THE PLAINS AND UPPER 20S OVER THE MOUNTAINS. THE FRONT SHOULD DROP INTO THE FORECAST AREA DURING THE AFTERNOON WITH SNOW INCREASING INTENSITY OVER THE PLAINS AS FLOW GOES UPSLOPE. HAVE INCREASED POPS OVER EAST FACING SLOPES AS FLOW GOES UPSLOPE THROUGH 700 MB. ECMWF SLIGHTLY SLOWER WITH THIS SYSTEM BUT BELIEVE THE BRUNT WILL BE MONDAY NIGHT INTO TUESDAY. TEMPERATURES WITH THIS SYSTEM LOOK TO KEEP MAX TEMPS TUESDAY AND WEDNESDAY IN THE TEENS TO SINGLE DIGITS AND MINIMUMS ZERO OR BELOW THROUGH WEDNESDAY NIGHT. WEDNESDAY WILL BE A DRIER DAY WITH THE WARMER AIR KICKING IN THURSDAY AS THE WEST COAST UPPER RIDGE MOVES INLAND. WE WILL STILL BE IN NORTHWEST FLOW HOWEVER SO KEPT POPS IN THE MOUNTAINS. AVIATION...ILS LANDING CONDITIONS ARE EXPECTED TO PREVAIL TIL 03Z WITH IMPROVING CONDITIONS THEREAFTER AS WESTERLY DOWNSLOPE FLOW WORKS OFF THE FOOTHILLS. UNTIL THEN...CANT RULE OUT A FEW LIGHT SNOW SHOWERS BUT TIMING OF THESE WILL BE DIFFICULT SO VCSH WILL BE THE PREVAILING FORECAST. ANY SNOW THAT DOES OCCUR WILL BE LIGHT WITH NOT MUCH VISIBILITY OBSCURATION. THE LOWEST VISIBILITY OBSERVED EARLIER TODAY WAS 2 1/2 MILES...AND OVERALL INTENSITY HAS BEEN DECREASING...SO PERHAPS BRIEF MVFR CONDITIONS TIL 03Z. THEN VFR THROUGH SATURDAY MORNING. COLD FRONTAL PASSAGE EXPECTED AROUND NOON SATURDAY WITH SNOW SHOWERS BECOMING LIKELY IN THE AFTERNOON WITH GUSTY NORTH WINDS BEHIND THE FRONT. IFR CONDITIONS ARE EXPECTED TO DEVELOP SHORTLY AFTER THE FRONT WITH POTENTIAL FOR AN INCH OR TWO OF SNOWFALL SATURDAY AFTERNOON/EVENING...AND PERHAPS HIGHER THAN THAT ESPECIALLY AT KAPA IF WINDS TURN MORE INTO THE FOOTHILLS. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 AM SATURDAY TO MIDNIGHT MST SATURDAY NIGHT FOR COZ033-034. WINTER STORM WARNING UNTIL MIDNIGHT MST SATURDAY NIGHT FOR COZ031. && UPDATE...RJK SHORT TERM...BARJENBRUCH LONG TERM....KRIEDERMAN AVIATION...BARJENBRUCH
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1100 AM MST FRI FEB 04 2011 COZ030>051-051300- 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- 1100 AM MST FRI FEB 04 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW SHOWERS WILL BE ON THE INCREASE TODAY IN THE MOUNTAINS WITH AROUND AN INCH OF SNOW BY LATE AFTERNOON...AND ANOTHER 1 TO 3 INCHES OVERNIGHT. ON THE PLAINS...SCATTERED SNOW SHOWERS WILL BE POSSIBLE THROUGH THE EARLY EVENING HOURS. MOST LOCATIONS WILL SEE LITTLE IF ANY SNOWFALL...BUT A FEW SPOTS MAY SEE ACCUMULATIONS UP TO 1 INCH. HOWEVER...TEMPERATURES WILL BE WARM ENOUGH TO ALLOW MOST OF THIS SNOW TO MELT ON PAVED SURFACES. EVEN A BIT OF LIGHT RAIN MAY MIX IN WITH THE SNOW AT TIMES. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A NORTHWEST FLOW ALOFT WILL BRING PERIODS OF SNOW TO THE NORTH CENTRAL MOUNTAINS SATURDAY THROUGH TUESDAY. SOME MOUNTAINS LOCATIONS MAY PICK UP OVER A FOOT OF SNOW BY TUESDAY...WITH LOCATIONS OVER THE NORTHERN GORE RANGE POSSIBLY SEEING UP TO TWO FEET. SNOWFALL WILL BE THE HEAVIEST SATURDAY DURING THE DAYTIME...THEN SUNDAY NIGHT THROUGH MONDAY. WINDS WILL BE QUITE STRONG AS WELL SUNDAY NIGHT THROUGH MONDAY PRODUCING AREAS OF BLOWING SNOW. OVER THE PLAINS...THERE WILL LIKELY BE A FEW SNOW SHOWERS SATURDAY AS THE NEXT SYSTEM AND A COLD FRONT BRINGS A ROUND OF COOLER TEMPERATURES AND SNOW SATURDAY NIGHT THROUGH SUNDAY. AMOUNTS OF 1 TO 2 INCHES COULD BE POSSIBLE WITH THE HIGHEST AMOUNTS OVER THE SOUTHERN METRO AREA OVER THE PALMER DIVIDE. DISTURBANCES IN THE NORTH-NORTHWEST FLOW MAY BRING A FEW PERIODS OF LIGHT SNOW TO NORTHEAST COLORADO MONDAY. STRONG WEST WINDS MONDAY WILL BRING WARM TEMPERATURES BEFORE ANOTHER ARCTIC COLD FRONT SHOULD PUSH THROUGH THE STATE MONDAY NIGHT BRINGING A ROUND OF COLD TEMPERATURES AND ANOTHER COUPLE OF INCHES OF SNOW FOR TUESDAY. AN UPPER RIDGE WILL BEGIN BUILDING TO BRING WARMER AND DRIER WEATHER FOR WEDNESDAY AND THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. BARJENBRUCH/KRIEDERMAN
The national radar mosaic for the moment the first event began.
2 winter storm, 2 winter weather. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2011Every state in 2011This day in weather historyWarnings in Colorado, February 2011
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: 281390, 281391, 281392, 281393.