Following the passage of the cold front, heavy snow occured during the evening in and near the Front Range Foothills and Palmer Divide. Snowfall totals included: 7 inches, 8 miles north of Blackhawk, Ken Caryl and 5 miles southeast of Sedalia, 6 inches at Coal Creek Canyon, Eldorado Springs, Lookout Mountain, 5 inches at Chief Hosa, Louisville, Rollinsville and Wheat Ridge, with 4 inches at…
Every event with a place to put it; 5 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.
Following the passage of the cold front, heavy snow occured during the evening in and near the Front Range Foothills and Palmer Divide. Snowfall totals included: 7 inches, 8 miles north of Blackhawk, Ken Caryl and 5 miles southeast of Sedalia, 6 inches at Coal Creek Canyon, Eldorado Springs, Lookout Mountain, 5 inches at Chief Hosa, Louisville, Rollinsville and Wheat Ridge, with 4 inches at Aurora, Bailey, Castle Rock, 5 miles northeast of Elizabeth, 11 miles southwest of Morrison and Parker.
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 May 20, 3:15 PM MST, 1 hour 45 minutes earlier.
NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
415 PM MDT SUN MAY 20 2001
...UPDATE FOR ISSUANCE OF HIGH WIND WARNING...
CDFNT ACCELERATED DOWN OFF THE CHEYENNE RIDGE WITH WIND GUSTS OF 60
TO 70 MPH BEING REPORTED IN LARIMER AND WELD COUNTIES. FRONT HAS
ALSO KICKED OFF A GUST TO 49 KTS AT KDEN SO FAR. HIGH WIND WARNING
FOR MUCH OF THE NE PLAINS HAS RESULTED. STRONGEST WINDS ARE ALONG
AND JUST BEHIND THE FRONT...SO WARNING IS ONLY IN EFFECT UNTIL 7 PM.
SHORT TERM DISCUSSION: A VERY POTENT STORM FOR THIS LATE IN THE
SEASON WL MOVE OVR THE FCST AREA TONITE. STG CDFNT WAS MOVG THRU
KCYS AT 20Z WITH THEIR RADAR SHOWING 35 KT WINDS BEHIND IT. MSAS
3HR PRES CHANGE CHART SHOWS A PLUS 6 BULLSEYE OVR KRIW.
POST-FRONTAL TEMPS IN CENTRAL WY DROPPED TO FREEZING DURING THE AFTN
WITH PERIODS OF MOD SNOW. CDFNT SHUD REACH DEN BTWN 4 AND 6 PM WITH
STRONG N WINDS AND RAPIDLY FALLING TEMPS. THE SHOWER ACTIVITY ALG
AND BEHIND THE FRONT HAS BEEN QUICK TO CHANGE OVR TO SNOW BECAUSE OF
THE STRONG COLD ADVECTION WITH THE SYSTEM. RADARS IN WY HAVE ALSO
BEEN SHOWING SNOW ECHOES IN THE 30-40 DBZ RANGE...INDICATIVE OF 1-2
INCH/HR SNOW INTENSITIES. 700-500MB OMEGA FIELDS FM THE MODELS SHOW
VALUES OVR NE CO IN EXCESS OF 12 MICROBARS/SEC...SO LOTS OF VERTICAL
MOTION TO GENERATE HEAVY PCPN THIS EVENING. BY MIDNIGHT...THINGS
SHUD BEGIN WINDING DOWN AS MODELS SHOW THE MAIN AREA OF LIFT
DROPPING INTO SERN CO. WARM GROUND SHUD HELP TO MELT MOST OF THE
SNOW THAT FALLS...BUT IN ZONES 35...36 AND 41...ENHANCED UPSLOPE
FORCING AND HIGHER ELEVATIONS COULD ALLOW A FEW INCHES OF SNOW TO
ACCUMULATE. THE STRONGEST WINDS WILL BE RIGHT ALONG THE FRONT...AND
WHEN HEAVIER SNOW DVLPS THE WINDS SHOULD SLACK OFF. SINCE IT IS SO
LATE IN THE SEASON...AND CONDS CUD GET BAD FOR A FEW HOURS...WL
ISSUE A S/BS ADVISORY FOR TONITE.
LONG TERM DISCUSSION: A COOL DAY IS IN STORE FOR MONDAY BUT AMS
SHUD BEGIN STABILIZING AS THE STRONG TROF MOVES EWD AND HIGH PRES
BUILDS IN FM THE W. WX WL BE DRY...BUT THIS AFTN'S SATELLITE
PICTURES SHOW QUITE A BIT OF CLD COVER IN MT FOR NOW. WL GO WITH A
PARTLY CLOUDY DAY AS SUBSIDENCE WL CAP MOST CONVECTION THRU THE
AFTN. AMS SHUD MODERATE ENOUGH ON MON AND MON NITE TO END THE
THREAT OF FREEZING TEMPS AT LOWER ELEVS TUES MRNG. BY MID-WEEK WE
WL BE UNDER A STRONG HIGH-AMPLITUDE RIDGE AXIS... ALLOWING FOR WARM
TEMPS AND DRY WX. BY THE END OF THE WEEK...SOME LOW LVL MSTR WL
RETURN FM THE GULF WHILE THE UPR RIDGE REMAINS IN PLACE. WL KEEP
THE EXTENDED FCST DRY AND SEASONAL THRU FRI...THEN INTRODUCE A
CHANCE OF AFTN THUNDERSTORMS FOR MEMORIAL DAY WEEKEND.
KDRBY
.DEN...HIGH WIND WRNG NERN CO PLAINS TIL 7 PM...ZNS 38>51.
S/BS ADVSY TONITE FNT RANGE FTHLS AND PALMER DIVIDE...ZNS
35..36..41.
OLOCAL STORM REPORT...CORRECTION
NATIONAL WEATHER SERVICE DENVER CO
541 PM MDT SUN MAY 20 2001
...PRELIMINARY STORM REPORT FOR MAY 20 2001...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0357 PM FORT COLLINS CO 71 MPH NON TSTM WIND GUST
05/20/01 LARIMER
0415 PM BROOMFIELD CO NON TSTM WINDS
05/20/01 JEFFERSON 2 INCH TREE LIMBS BROKEN
0410 PM 6 SW WELLINGTON CO 61 MPH NON TSTM WIND GUST
05/20/01 LARIMER
0530 PM 15 E PARKER CO 68 MPH NON TSTM WIND GUST
05/20/01 ELBERT
0345 PM HORSETOOTH INLET BAY CO NON TSTM WINDS
05/20/01 LARIMER 2 INCH TREE LIMBS BROKEN
0500 PM 5 NW ELIZABETH CO NON TSTM WINDS
05/20/01 ELBERT LARGE TREE BLOWN DOWN
0435 PM GREELEY AIRPORT CO 83 MPH NON TSTM WIND GUST
05/20/01 WELD
JKThe national radar mosaic for the moment the first event began.
5 heavy snow. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2001Every state in 2001This day in weather historyWarnings in Colorado, May 2001
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: 5250144, 5250145, 5250146, 5250147, 5250148.