A band of heavy snow, produced around one inch in less than 30 minutes, contributed to a chain of accidents in the northbound lanes of Interstate 25, between Logan Street and University Boulevard. The combination of excessive speed and very poor driving conditions led the chain reaction; it involved 104 vehicles and resulted in one death along with 30 injuries.
Every event with a place to put it; 1 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 band of heavy snow, produced around one inch in less than 30 minutes, contributed to a chain of accidents in the northbound lanes of Interstate 25, between Logan Street and University Boulevard. The combination of excessive speed and very poor driving conditions led the chain reaction; it involved 104 vehicles and resulted in one death along with 30 injuries. The interstate was closed for approximately 5 hours.
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 Mar 1, 7:49 AM MST, 2 hours 36 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 749 AM MST SAT MAR 1 2014 .UPDATE...DENVER CYCLONE AND DEEPENING MOISTURE HAS PRODUCED A LARGE AREA OF DENSE FOG OVER THE SOUTHERN METRO AREAS...PALMER DIVIDE AND EAST OUT OVER I 70 TOWARD LIMON. HAVE ISSUED A DENSE FOR ADVISORY FOR THESE AREAS AS WE'RE EXPECTED VISIBILITIES LESS THAN 100 YARDS FOR THE NEXT FEW HOURS OUT THERE. SOME HEAVIER BANDS OF SNOW HAVE MOVED OFF THE MOUNTAINS AND OVER THE WESTERN URBAN CORRIDOR...INCLUDING BOULDER COUNTY AND PARTS OF EASTERN LARIMER AND WESTERN WELD COUNTIES. PERIODS OF HEAVY SNOW WILL OCCUR UNDER THESE BANDS BUT ARE NOT EXPECTED TO LAST LONG. THIS SNOW WILL BE LESSENING THE AMOUNT OF FREEZING DRIZZLE. HOWEVER THERE WILL STILL BE AREAS OF SLICK ROADS DUE TO THE FREEZING DRIZZLE EARLIER THIS MORNING. && .AVIATION...HAVE EXTENDED THIS MORNINGS VLIFR CONDITIONS WITH CYCLONE WELL ENTRENCHED. EXPECT SOME IMPROVEMENT TO BEGIN BETWEEN 17-18Z. LOW CLOUDS WILL PREVAIL THROUGH THE NEXT 24 HOURS. CEILINGS WILL SLOWLY RISE THROUGH THE DAY BUT REMAIN BELOW 2000 FEET. AREAS OF SNOW WILL CONTINUE THROUGH THE DAY. AFTER 00Z...CLOUDS WILL LOWER AGAIN. CEILINGS BELOW 500 FEET WITH FOG WILL BE POSSIBLE AFTER 03Z TONIGHT. && .PREV DISCUSSION... /ISSUED 350 AM MST SAT MAR 1 2014/ SHORT TERM...TODAY AND TONIGHT...MOIST SOUTHWEST FLOW AHEAD OF A STRONG PACIFIC SYSTEM WILL BE OVER THE MOUNTAINS TODAY. EXPECT PERIODS OF SNOW TO CONTINUE. WEB CAMERAS JUST SHOWING LIGHT SNOWFALL SO FAR ALONG INTERSTATE 70 IN THE MOUNTAINS. BETTER SNOWFALL HAS OCCURRED OVER THE NORTHERN MOUNTAINS ACCORDING TO SNOTEL STATIONS. SATELLITE SHOWING A GOOD MOISTURE PLUME FROM WESTERN COLORADO SOUTH TO EASTERN ARIZONA. THIS WILL SHIFT EASTWARD TODAY. STILL EXPECT TO SEE A PERIOD OF MODERATE TO HEAVY SNOW OVER THE MOUNTAINS THIS MORNING. SNOW WILL DECREASE A LITTLE THIS AFTERNOON...HOWEVER LAPSE RATES STEEPEN SO COULD SEE SOME CONVECTION AND BRIEF PERIODS OF HEAVY SNOW. WILL KEEP THE ADVISORIES GOING. WILL ADD ZONE 33 TO THE ADVISORY SINCE IT IS SEEING MORE SNOW THAN ZONE 34 WHICH IS IN THE ADVISORY. SNOW WILL BECOME LIGHT TONIGHT AS DRIER AIR MOVES OVER THE MOUNTAINS. ADDITIONAL SNOWFALL WILL BE LIGHT...SO PLAN ON LETTING THE ADVISORY EXPIRE AT 6 PM. FOR THE FRONT RANGE AND PLAINS...SHALLOW ARCTIC AIRMASS HAS MOVED INTO THE AREA. JUST ABOVE IT...DRIER SOUTH TO SOUTHWEST WINDS PREVAIL. THIS WILL PRODUCE DOWNSLOPE CONDITIONS JUST ABOVE THE ARCTIC. AREAS OF FOG AND FREEZING DRIZZLE ARE OCCURRING. ROADS WILL BE ICY IN SPOTS...ESPECIALLY ON BRIDGES AND OVERPASSES THIS MORNING. A DENVER CYCLONE WILL KEEP NORTHERLY WINDS...LOW CLOUDS AND COOL TEMPERATURES OVER THE DENVER AREA. SOUTHERLY WINDS OFF THE PALMER DIVIDE WILL ALLOW TEMPERATURES TO CLIMB ABOVE 40 DEGREES ALONG THE PALMER DIVIDE. BEST CHANCE FOR SNOW TODAY WILL BE FAR NORTH WHERE THE BEST DIFFLUENCE AND MOISTURE WILL BE. STEEPER LAPSE RATES AND LIFT FROM THE JET COULD PRODUCE SNOW SHOWERS THIS AFTERNOON AND EVENING OVER NORTHEAST COLORADO. AIRMASS WILL BE SOMEWHAT DRY ABOVE THE ARCTIC...SO THINKING JUST SCATTERED SNOW THROUGH EVENING THEN ENDING AFTER MIDNIGHT. EXPECT LOW CLOUDS...FOG AND DRIZZLE AGAIN TONIGHT FOR PARTS OF NORTHEAST COLORADO. LONG TERM...THE DEEP LAYER CLOSED LOW SPIRALLY OFF THE CENTRAL CALIF COAST AT THE PRESENT TIME IS PROGGED TO SHEAR APART INTO A LOW AMPLITUDE SHORTWAVE TROUGH AS IT TRACKS EAST ACROSS THE LOWER GREAT BASIN AND LATER OVER THE FOUR CORNERS REGION SUNDAY MORNING. IT APPEARS THIS SYSTEM WILL STILL CONTAIN SUFFICIENT MARITIME MOISTURE TO SUPPORT AREAS OF LIGHT SNOWFALL FOR HIGHER ELEVATIONS IN NORTH CENTRAL COLORADO ON SUNDAY...PARTICULARLY IN THE MORNING WITH COOLING ALOFT PRODUCING MARGINALLY UNSTABLE LAPSE RATES OVER THE AREA. MEAN LAYER FLOW ALSO BECOMES NORTHWESTERLY WHICH WOULD FAVOR SNOWFALL ON NORTHWEST EXPOSURES. ADDITIONAL SNOW ACCUMULATIONS SHOULD BE LIGHT. FOR THE PLAINS...MODELS SHOW THE ARCTIC AIR REMAINING IN PLACE SUNDAY WITH LIGHT EASTERLY BOUNDARY LAYER FLOW. CROSS SECTIONS ALSO INDICATE AN EXTENSIVE COVER OF LOW CLOUDS ON THE PLAINS THROUGH LATE MORNING. THEN A GRADUAL WEST-TO- EAST BURN OFF DURING THE REMAINDER OF THE DAY WITH THE UPSLOPE GRADIENT WEAKENING AND AS SUBSIDENCE AND DRYING TAKE HOLD. IT/S POSSIBLE AREAS NEAR THE FOOTHILLS COULD SEE A FEW FLURRIES OR FREEZING DRIZZLE EARLY SUNDAY MORNING...ENOUGH TO WARRANT AT 10 PCT POP. OTHERWISE SUNDAY PRETTY MUCH LOOKS DRY FOR THE PLAINS. THERE IS STILL SOME QUESTION AS TO HOW WARMING WE/LL SEE SUNDAY. COULD SEE ONE OF THOSE SETUPS WHERE LIGHT WESTERLY BREEZES SEND AFTERNOON TEMPERATURES INTO THE UPPER 30S/LOWER 40S ON THE PALMER DIVIDE AND ALONG THE BASE OF THE FOOTHILLS INCLUDING WESTERN AND SOUTHWESTERN SECTIONS OF THE DENVER METRO AREA. ELSEWHERE ON THE PLAINS HIGH TEMPERATURES WILL PROBABLY NOT CLIMB OUT OF THE TEENS AND 20S WITH COLDEST READINGS NEAR THE NEBRASKA BORDER...EVEN WITH THE CLEARING SKIES. SUNDAY NIGHT INTO MONDAY...MODELS SHOW THE ARCTIC AIR ON THE PLAINS SLOWLY FLUSHING OUT SUNDAY NIGHT/MONDAY MORNING WITH RESUMPTION OF A MORE TYPICAL DOWNSLOPE/DOWNVALLEY FLOW PATTERN. HOWEVER LOW LYING AREAS ALONG THE SOUTH PLATTE AND DOWNSTREAM FROM DENVER WILL LIKELY SEE ONE MORE VERY CHILLY NIGHT WITH THE ARCTIC AIR TRAPPED BENEATH A STRONG SFC BASED INVERSION. ON MONDAY...THE NAM...GFS AND CANADIAN GEM INDICATE A BIG WARMUP FOR MOST OF THE CWFA WITH RISING HEIGHTS/WARMING ALOFT...DOWNSLOPE FLOW EAST OF THE MTNS AND MORE SUNSHINE. WHEREAS THE ECMWF PAINTS A DIFFERENT PICTURE. IT SHOWS FALLING HEIGHTS/COOLING ALOFT WITH THE PASSAGE OF A WEAK SHORTWAVE TROUGH. THE EC ALSO GENERATES SOME LIGHT QPF/SNOWFALL IN THE HIGH COUNTRY DURING THE DAY. NAM AND THE GEM ALSO INDICATE SPOTTY LIGHT QPF UP THERE. FCST GRIDS ALREADY HAVE SCATTERED POPS IN THE HIGH COUNTRY ON MONDAY. DON/T SEE TO NEED TO CHANGE THAT. FOR THE PERIOD TUESDAY-FRIDAY...MODELS INDICATE A CONTINUATION OF WEST-NORTHWEST FLOW ALOFT WITH THE QUICK PASSAGE OF A WEAK SHORTWAVE TROUGH TUESDAY NIGHT AND A STRONG UPPER RIDGE ON THURSDAY. MOS TEMPERATURE GUIDANCE INDICATES A SLOW BUT STEADY DAY-TO-DAY WARMUP THROUGH THURSDAY WITH THE WARMEST READINGS ON THURSDAY UNDER THE RIDGE. AFTER THE SHOT OF LIGHT SNOW IN THE HIGH COUNTRY TUESDAY AFTERNOON/NIGHT...THE CWFA SHOULD REMAIN DRY UNTIL THURSDAY NIGHT. THURSDAY NIGHT AND FRIDAY...00Z RUN OF THE MODELS INDICATE THE PASSAGE OF ANOTHER SHORTWAVE TROUGH AND SFC COLD FRONT DURING THE DAY FRIDAY. THIS WOULD DROP TEMPERATURES AND POSSIBLY GIVE THE MTNS AND PLAINS A CHANCE OF SNOW. AVIATION...LOW CLOUDS WILL PREVAIL THROUGH THE NEXT 24 HOURS. CEILINGS BELOW 500 FEET AND FOG WITH VISIBILITY AS LOW AS A QUARTER MILE IS EXPECTED TO CONTINUE THROUGH 16Z. CEILINGS WILL SLOWLY RISE THROUGH THE DAY BUT REMAIN BELOW 2000 FEET. AFTER 00Z...CLOUDS WILL LOWER AGAIN. CEILINGS BELOW 500 FEET WITH FOG WILL BE POSSIBLE AFTER 03Z TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ031- 033-034. DENSE FOG ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ041-046- 047. && SHORT TERM...MEIER LONG TERM....BAKER UPDATE/AVIATION...KRIEDERMAN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 940 AM MST SAT MAR 1 2014 COZ030>051-021645- 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- 940 AM MST SAT MAR 1 2014 ...WINTER WEATHER ADVISORY FOR THE MOUNTAINS THROUGH 6 PM... ...DENSE FOG ADVISORY FOR THE SOUTHERN METRO AREAS AND PALMER DIVIDE EAST TO LIMON THROUGH 11 AM... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT A PACIFIC STORM SYSTEM MOVING ACROSS THE AREA WILL CONTINUE TO BRING SNOW TO THE MOUNTAINS. SNOWFALL AMOUNTS OF 4 TO 10 INCHES WILL ACCUMULATE IN THE HIGH COUNTRY THROUGH TODAY...WITH AS MUCH AS A FOOT OF SNOW IN THE MOUNTAINS ALONG AND NORTH OF RABBIT EARS PASS. SNOW WILL DECREASE IN THE MOUNTAINS TONIGHT. MEANWHILE OVER NORTHEAST COLORADO...IT WILL BE COLD TODAY WITH HIGHS IN THE TEENS AND 20S. THERE WILL BE AREAS OF FOG...FREEZING DRIZZLE AND SNOW THIS MORNING. BANDED SNOW WILL BE PRODUCING SNOWFALL AMOUNTS OF 2 TO 4 INCHES OVER AREAS ALONG AND NORTH OF INTERSTATE 70. SOME ROADS MAY BE SLIPPERY...ESPECIALLY BRIDGES AND OVERPASSES. LIGHT SNOW WILL ALSO BE POSSIBLE THIS AFTERNOON WITH LESS BANDING EXPECTED. AREAS OF FOG AND FREEZING DRIZZLE ARE EXPECTED TO REFORM TONIGHT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY IT WILL REMAIN COLD ON SUNDAY WITH LOW CLOUDS AND AREAS OF FOG ON THE PLAINS DURING THE MORNING...AND LIGHT SNOWFALL THROUGHOUT THE DAY IN THE HIGH COUNTRY. DRY AND MUCH WARMER WEATHER CAN BE EXPECTED PARTICULARLY ON THE PLAINS MONDAY. THERE IS A ANOTHER CHANCE OF SNOW IN THE HIGH COUNTRY TUESDAY WITH THE PASSAGE OF WEAK UPPER LEVEL WEATHER DISTURBANCE. WEDNESDAY AND THURSDAY...DRY CONDITIONS AND ABOVE AVERAGE TEMPERATURES ARE IN STORE AS THE OUTLOOK AREA COMES UNDER THE INFLUENCE OF A STRONG RIDGE OF HIGH PRESSURE. IT WILL THEN TURN COOLER FRIDAY WITH THE PASSAGE OF A COLD FRONT. THERE WILL BE A CHANCE OF SNOW IN THE HIGH COUNTRY THAT DAY...AND A SLIGHT CHANCE OF RAIN AND SNOW AT LOWER ELEVATIONS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
921 AM MST SAT MAR 01 2014
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0915 AM SNOW 2 NW FORT COLLINS 40.58N 105.09W
03/01/2014 M2.6 INCH LARIMER CO TRAINED SPOTTER
1 INCH IN LAST 30 MINUTES
0911 AM SNOW 2 SSW BOULDER 40.00N 105.27W
03/01/2014 M2.1 INCH BOULDER CO NWS EMPLOYEE
0905 AM SNOW N LONGMONT 40.17N 105.11W
03/01/2014 M1.1 INCH BOULDER CO TRAINED SPOTTER
0830 AM SNOW 1 SSE BRECKENRIDGE 39.49N 106.04W
03/01/2014 M2.6 INCH SUMMIT CO TRAINED SPOTTER
&&PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
1000 AM MST SAT MAR 01 2014
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0958 AM SNOW 3 S BOULDER 39.98N 105.25W
03/01/2014 M3.2 INCH BOULDER CO TRAINED SPOTTER
0951 AM SNOW 2 SSW BOULDER 40.00N 105.27W
03/01/2014 M3.1 INCH BOULDER CO NWS EMPLOYEE
DAVID SKAGGS RESEARCH CENTER NOAA
0944 AM SNOW 2 N FORT COLLINS 40.58N 105.07W
03/01/2014 M2.4 INCH LARIMER CO TRAINED SPOTTER
0915 AM SNOW 2 NW FORT COLLINS 40.58N 105.09W
03/01/2014 M2.6 INCH LARIMER CO TRAINED SPOTTER
1 INCH IN LAST 30 MINUTES
0905 AM SNOW N LONGMONT 40.17N 105.11W
03/01/2014 M1.1 INCH BOULDER CO TRAINED SPOTTER
0830 AM SNOW 1 SSE BRECKENRIDGE 39.49N 106.04W
03/01/2014 M2.6 INCH SUMMIT CO TRAINED SPOTTER
&&
KFREDINThe national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Winter Weather, N Douglas County Below 6000 Feet / Denver / W Adams & Arapahoe Counties / E Broomfield County | 2014-03-01 | 1 | Female | Vehicle/Towed Trailer | Indirect |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2014Every state in 2014This day in weather historyWarnings in Colorado, March 2014
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: 508725.