Colorado, 2001Flash Flood in Colorado, July 12, 2001
July 12, 2001 · NWS BOU · 1 event in 1 county or zone
1 flash flood, as filed by the National Weather Service.
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.
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
What forecasters said that day
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 Jul 12, 1:40 PM MST, 50 minutes earlier.
Area forecast discussion, Jul 12, 1:40 PM MST, 50 minutes before
NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
240 PM MDT THU JUL 12 2001
ALL COMPONENTS COMING TOGETHER ONCE AGAIN FOR SCATTERED HEAVY
RAINERS IN THE BOU CWA. THE TROPICAL MOISTURE PLUME REMAINS OVER
THE SOUTHERN AND CENTRAL ROCKY MOUNTAINS AND DAYTIME BRIGHTENING IN
THE H20 TAKING PLACE A LITTLE EARLIER THAN PREVIOUS FEW DAYS. ETA
DOES SHOW SOME WEAK VORTICITY AND QG LIFT ASSOCIATED WITH THE
BRIGHTENING THIS EARLY AFTERNOON WITH ANOTHER BATCH OF RISING AIR IN
EXTREME NORTHEAST AZ. DEN 12Z SOUNDING EVEN MORE MOIST WITH NO
INDICATION OF SIGNIFICANT MID LVL STABILITY HERE...GJT...SLC OR
ABQ. ON THE GROUND...THETA-E GRADIENT PRESENT AGAIN IN THE MSAS
DATA WITH THE HIGHEST VALUES IN THE PLATTE VALLEY AND BEST GRADIENT
RUNNING ALONG THE URBAN CORRIDOR AND PALMER DIVIDE. EAST TO
NORTHEAST SFC FLOW SHD CONTINUE UNTIL DUSK WITH THE TOTH-JOHNSON
SUMMERTIME WIND FLOW REGIME UNDER WEAK FLOW ALOFT. MESO-ETA ALSO
CONTINUES THE NORTHEASTERLY FLOW AS IT HOLDS THE GRADIENT TIGHT AND
ALSO HINTS AT THE MOST PRECIPITATION DEVELOPING IN SOUTHERN SECTIONS
OF CWA. FLASH FLOOD WATCH ALREADY SENT OUT TO REFLECT THIS AND MAY
NEED TO BE EXPANDED. THIS MORNINGS ETA SHOWS THE 700MB AND 500MB
HGTS RIDGE AXIS OVER THE FRONT RANGE AT 18Z AND STEERING FLOW ALOFT
ALREADY PUSHING STORMS EAST TO NORTHEASTWARD. WILL EXPECT STORMS
OUT ONTO THE PLAINS BY THE EVENING HOURS. AT ANY DIRECTION...STORM
MOTION WILL BE SLOW. CURRENT FCST LOOKS GOOD WITH SCT COVERAGE WITH
THE MENTION OF HEAVY RAIN. MDLS THEN SHOW AND MCS PUSHING OUT OF
THE EASTERN PLAINS LATE TONIGHT. FOR FRIDAY...SFC MOISTURE STILL
PRESENT ON THE PLAINS...HOWEVER HIGHEST IN SOUTHEAST COLO...AND
SOUTHEASTERLY WINDS ARE EXPECTED ALONG WITH A POSSIBLE DENVER
CONVERGENCE ZONE SETTING UP. ETA AND AVN HAVE ANOTHER VORT MAX
SWEEPING OVER NORTHERN COLO BY MID AFTERNOON WHICH COULD SET THINGS
OFF AGAIN. STEERING WINDS SHOULD BE MORE PROGRESSIVE FRI AND SCT
COVERAGE WOULD SEEM TO FIT FOR TOMORROW AFT AND EVE. GOING INTO
SATURDAY...WONT DEVIATE FROM CURRENT FCST OF SCT COVERAGE. UPPER
RIDGE IS WEAKENING BY LATE SATURDAY WITH A STRONGER SHORT WAVE TROF
ARRIVING BY LATE AFTERNOON AND FLATTENING THE TOP OF THE RIDGE.
850MB AVN WINDS TREND SOUTHWESTERLY EARLY SUN WITH DRYER AIR ALOFT
WORKING IN OVER THE GREAT BASIN.
EXTENDED PD...SUNDAY THROUGH THURSDAY...UPPER RIDGE TRENDING TO A
LESS FAVORABLE PATTERN FOR SUMMERTIME TROPICAL FLOW INTO THE
ROCKIES. UPPER TROF DEEPENS INTO CENTRAL CALIFORNIA BY SUN STEERS
UPPER FLOW FROM THE SOUTH PACIFIC INSTEAD OF MEX. BY TUES...MRF
PREDICTS CENTER OFTHE HIGH OVR ERN KANSAS WITH NORTHWESTERLY FLOW
ALOFT PREVAILING OVER THE ENTIRE WESTERN HALF OF THE U.S. THROUGH
THURSDAY. WILL KEEP THE LOWERED CHANCE FOR STORMS TUE...WED AND
THUR BUT DRYEST LOOKS TO BE THURS. TEMP GUIDANCE HOLDING NEAR
SEASONAL NORMALS THROUGH ENTIRE PD. FREDIN
.DEN...FLASH FLOOD WATCH...35>36..38>41..43.
In the hours before
Special weather statement, Jul 12, 9:30 AM MST, 5 hours before
COZ030>051-122000-
SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1030 AM MDT THU JUL 12 2001
THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES
ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS
ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER
LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK
SUMMIT WASHINGTON WELD
SYNOPSIS...A MOIST SOUTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS
NORTHEAST COLORADO THIS AFTERNOON AND TONIGHT. THE MAIN FOCUSING
MECHANISM FOR THUNDERSTORMS TODAY WOULD APPEAR TO BE ALONG THE FRONT
RANGE FOOTHILLS AND PALMER DIVIDE WHERE A STATIONARY FRONT HAS
PARKED ITSELF. NO OTHER DISTINCT BOUNDARIES ARE EVIDENT THIS
MORNING.
THE STORMS WILL BE VERY SLOW MOVING TODAY. THE STRONGER STORMS
COULD PRODUCE 1.5 TO 2.5 INCHES OF RAIN IN AN HOUR ALONG WITH
FREQUENT CLOUD TO GROUND LIGHTNING. THE POSSIBILITY OF AN ISOLATED
SEVERE THUNDERSTORM IS NOT OUT OF THE QUESTION...WITH HAIL UP TO 1
INCH IN DIAMETER AND DAMAGING WINDS IN EXCESS OF 55 MPH POSSIBLE.
URBAN AND SMALL STREAM FLOODING WILL LIKELY OCCUR WITH ANY OF THE
THUNDERSTORMS TODAY. IF A FLASH FLOOD WATCH IS ISSUED...THE MAIN
AREA OF CONCERN APPEARS TO BE ALONG THE FRONT RANGE FOOTHILLS AND
PALMER DIVIDE...WEST AND SOUTH OF DENVER.
RESIDENTS IN THE HIGH MEADOWS...BUFFALO CREEK AND BOBCAT BURN AREAS
SHOULD BE ESPECIALLY ALERT TO HEAVY RAINFALL AS THE THRESHOLD FOR
FLASH FLOODING IS LOWER THERE THAN IN OTHER LOCATIONS.
SPOTTER ACTIVATION MAY ALSO BE NECESSARY LATE THIS AFTERNOON AND
EVENING.
k
COOPER
Special weather statement, Jul 12, 12:10 PM MST, 2 hours 20 minutes before
COZ030>051-122100-
SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
110 PM MDT THU JUL 12 2001
THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES
ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS
ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER
LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK
SUMMIT WASHINGTON WELD
SYNOPSIS...A MOIST SOUTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS
NORTHEAST COLORADO THIS AFTERNOON AND TONIGHT. THE MAIN FOCUSING
MECHANISM FOR THUNDERSTORMS TODAY WOULD APPEAR TO BE ALONG THE FRONT
RANGE FOOTHILLS AND PALMER DIVIDE WHERE A STATIONARY FRONT HAS
PARKED ITSELF.
AT 1PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SCATTERED THUNDERSTORMS DEVELOPING ACROSS THE FRONT RANGE FOOTHILLS
AND CHEYENNE RIDGE. THE STORMS WILL GRADUALLY INCREASE IN COVERAGE
AND INTENSITY THE REST OF THIS AFTERNOON...MOVING INTO THE REST OF
THE URBAN CORRIDOR BY THIS EVENING.
THE STORMS WILL BE VERY SLOW MOVING TODAY. THE STRONGER STORMS
COULD PRODUCE 2 TO 3 INCHES OF RAIN IN AN HOUR ALONG WITH FREQUENT
CLOUD TO GROUND LIGHTNING. A FLASH FLOOD WATCH HAS BEEN ISSUED
THROUGH 10 PM FOR THE URBAN CORRIDOR...FRONT RANGE FOOTHILLS AND
PALMER DIVIDE.
RESIDENTS IN THE HIGH MEADOWS...BUFFALO CREEK AND BOBCAT BURN AREAS
SHOULD BE ESPECIALLY ALERT TO HEAVY RAINFALL AS THE THRESHOLD FOR
FLASH FLOODING IS LOWER THERE THAN IN OTHER LOCATIONS.
THE POSSIBILITY OF AN ISOLATED SEVERE THUNDERSTORM IS NOT OUT OF THE
QUESTION...WITH HAIL UP TO 1 INCH IN DIAMETER AND DAMAGING WINDS IN
EXCESS OF 55 MPH POSSIBLE.
SPOTTER ACTIVATION MAY ALSO BE NECESSARY LATE THIS AFTERNOON AND
EVENING.
COOPER
Flash Flood, Larimer
- When
- July 12, 2:30 PM MST to 3:45 PM MST
- Where
- Larimer County, Berthoud
- Reported by
- NEWSPAPER
- Coordinates
- 40.666, -105.461 (the zone’s center; the record gives no point)
Heavy rain caused flooding and flash flooding problems in the Berthoud area. Some parts of town were under 2 to 3 feet of standing water. State Highway 287 was closed as high water covered the roadway. Some basements in the Berthoud Lake subdivision were inundated with up to 5 feet of water. Major crop damage was reported on the west side of town as 320 acres of corn, wheat and beets were flooded. The storm also caused the Burlington Northern/Santa Fe railroad to shut down tracks for 4 hours while repair crews fixed a 100-foot and 75-foot stretch of track the had been washed out.
- Flash Flood
- Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Flash Flood in Washington, July 12, 20011 death · $1.5 million · 1 event
- Heat in Mississippi, July 12, 20011 death · 1 event
- Heat in Texas, July 12, 20011 death · 1 event
- Flash Flood and Hail in Montana, July 12 to 13, 2001$340,000 · 2 in hail · 9 events
- Wildfire in California, July 12, 2001$350,000 · 1 event
- Flash Flooding and Hail in Montana, July 12, 2001$200,000 · 1.75 in hail · 11 events
- Hail and Damaging Winds in Mississippi, July 12, 2001$60,000 · 50 kt wind · 18 events
- Damaging Winds in Louisiana, July 12, 2001$42,000 · 7 events
- Hail and Damaging Winds in Oklahoma, July 12, 2001$20,000 · 56 kt wind · 4 events
- Lightning Strike in Colorado, July 12, 2001$20,000 · 1 event
- Hail and Damaging Winds in Kansas, July 12, 20011 in hail · 12 events
- Damaging Wind in Missouri, July 12, 2001$15,000 · 58 kt wind · 1 event
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: 5267274.