A thunderstorm producing heavy rain produced flash flooding in the Hayman burn scar. Two separate driveways were washed out.
Every event with a place to put it. 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 thunderstorm producing heavy rain produced flash flooding in the Hayman burn scar. Two separate driveways were washed out. Several logs and debris were discovered along Camp Creek. Debris also washed across State Highway 67.
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 29, 1:45 PM MST, 1 hour 45 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 245 PM MDT FRI JUL 29 2011 .SHORT TERM...SO FAR AFTERNOON STORMS CONFINED TO SOUTHERN FRONT RANGE FOOTHILLS AND PARK COUNTY. LOW LEVEL MOISTURE HAS MIXED OUT OVER THE URBAN CORRIDOR AS DEWPOINTS HAVE DROPPED INTO THE MID 30S TO LOWER 40S. STORMS HAVING A HARD TIME MAINTAINING THEMSELVES AS THEY MOVE OFF THE FOOTHILLS AS LAPS SHOWING CAPES DOWN TO 200-500J/KG. SURFACE MOISTURE HOLDING STEADY OVER THE EASTERN PLAINS BUT WILL REMAIN CAPPED OVER THE FAR NORTHEAST CORNER. BEST CHANCES WILL STILL BE OVER THE PALMER DIVIDE AND PARK COUNTY WHERE MOISTURE LEVELS ARE DEEPER. WILL LOWER POPS FURTHER OVER THE PLAINS EXCEPT ALONG OUR SOUTHERN CWA BORDERS. NOT REALLY MUCH CHANGE ON SATURDAY AS DEEPER MOISTURE WILL RESIDE OVER SOUTHERN COLORADO WITH HIGHEST CHANCES OVER THE SOUTHERN PORTIONS OF CWA...WITH MAINLY ISOLATED CHANCES FURTHER NORTH. HEIGHTS RISE EVEN FURTHER SO WILL SO FEW MORE DEGREES WARMING ON THE PLAINS. .LONG TERM...THE LARGE UPPER LEVEL RIDGE WITH ITS 597 DECIMETER HIGH OVER KANSAS/NRN OKLAHOMA WILL CONTINUE TO CIRCULATE HOT AND DRY AIR NORTHWARD OVER ERN COLORADO ON SUNDAY. AREAS EAST OF THE MTNS SHOULD ESCAPE SEEING ANY MEANINGFUL CONVECTION WITH STRONG MID-LEVEL CAP UNTIL EVENING. EVEN THEN...STORMS SHOULD BE LIMITED TO ALONG COLLIDING OUTFLOW BOUNDARIES AND OVER THE HIGHER TERRAIN OF THE PALMER DIVIDE WHILE MTN AREA SHOULD STILL SEE SCATTERED STORMS BY AFTERNOON AS THE FCST AREA WILL BE ON THE EDGE OF THE MONSOON MOISTURE PLUME. ON MONDAY...MODELS SHOW THE UPPER RIDGE SHIFTING WESTWARD OVER ERN COLORADO IN THE MORNING...THEN BACK OVR THE TEXAS/OKLAHOMA PANHANDLE REGION DURING THE AFTERNOON AND EVENING. THIS ALLOWS THE MONSOON MOISTURE PLUME JUST TO OUR WEST TO SHIFT EWRD OVER THE FRONT RANGE AND NERN PLAINS OF COLORADO BY LATE IN THE DAY. AS A RESULT SHOULD SEE STEADY MOISTENING AT MID-LEVEL THROUGH THE DAY BUT LOW LEVELS STILL REMAIN PRETTY DRY WITH DOWNSLOPING FLOW OFF THE FOOTHILLS. INVERTED-V MODEL SOUNDINGS INDICATE A GREATER CHANCE FOR MICROBURST WINDS FROM HIGH BASED CONVECTION AND LESS IN THE WAY OF WETTING RAINFALL EAST OF THE FRONT RANGE. MONDAY NIGHT AND TUESDAY...MODELS SHOW THE UPPER RIDGE SLIDING SOUTH OF COLORADO WHICH OPENS US UP TO A WETTER WEST-SOUTHWESTERLY FLOW ALOFT. MODELS ALSO SHOW A WEAK COLD FRONT BACKING INTO NERN COLORADO TUESDAY MORNING WHICH SETS UP A MOIST UPSLOPE FLOW EAST OF THE FRONT RANGE FOR THE REST OF THE DAY AND EVENING. COUPLE THIS WITH THE PASSAGE OF A WEAK UPPER AIR DISTURBANCE AROUND 00Z/WED AND CHANCES ARE WE/LL SEE A DECENT AMOUNT OF SLOW MOVING CONVECTION ACROSS THE FCST AREA SOME CAPABLE OF HEAVY RAINFALL. THIS WAVE MOVES EAST OVERNIGHT TAKING WITH IT MOST OF THE STORM ACTIVITY. ON WEDNESDAY...SEE A SIMILAR SETUP WITH MOIST UPSLOPE FLOW ON THE PLAINS AND PASSAGE OF ANOTHER WEAK SHORTWAVE IN THE AFTERNOON. WILL HANG ONTO THE HIGH SCATTERED POPS IN AND ALONG THE MTNS AND LOWER SCATTERED POPS FARTHER OUT ON THE PLAINS. BY THURSDAY...MODELS SHOW THE MONSOON MOISTURE PLUME SHEARS OUT TO THE SOUTH OF THE FCST AREA WITH THE UPPER RIDGE SHIFTING BACK OVER TEXAS. HOWEVER THE DAILY ROUND OF AFTERNOON AND EVENING THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH THE END OF THE WEEK. && .AVIATION...STORMS ARE HAVING A HARD TIME MAINTAINING INTEGRITY ONCE THEY DRIFT OF THE FOOTHILS AS DEWPOINTS HAVE DROPPED. HAVE ALREADY LOWERED DEN CHANCES TO VCTS BUT WILL KEEP TEMPO FOR NOW AT APA WITH CLOSER PROXIMITY TO CONVECTION OCCURRING ACROSS JEFFERSON AND DOUGLAS COUNTIES. SIMILAR PATTERN ON SATURDAY WITH ISOLATED POPS AGAIN...HIGHEST AT APA AGAIN. && .HYDROLOGY...PRECIPITABLE WATER VALUES JUST UNDER AN INCH BUT STILL POTENTIAL FOR HEAVY RAINS ACROSS SOUTHERN FOOTHILLS AND PALMER DIVIDE. STORM MOTIONS AROUND 10KT APPEAR HIGH ENOUGH TO KEEP OVERALL FLASH FLOOD THREAT ON THE LOW SIDE. THE CHANCE OF AFTERNOON AND EVENING STORMS WILL CONTINUE THROUGH THE WEEKEND OVER THE HIGHER TERRAIN...THEN SPREAD OVER THE PLAINS EARLY NEXT WEEK. A POTENTIAL FOR THE STORMS TO PRODUCE HEAVY RAIN WILL REMAIN AS FLOW ALOFT SHOULD BE RELATIVELY LIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && ENTREKIN/BAKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1114 AM MDT FRI JUL 29 2011 COZ030>051-301200- 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- 1114 AM MDT FRI JUL 29 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER THE FRONT RANGE FOOTHILLS AND PALMER DIVIDE THIS AFTERNOON...THEN SPREAD OVER THE ADJACENT PLAINS BY LATE AFTERNOON AND EARLY EVENING. THE MAJORITY OF THE STORMS WILL PRODUCE HEAVY RAIN...WIND GUSTS TO 45 MPH AND SOME SMALL HAIL. ACROSS THE FAR NORTHEAST PLAINS...THE ATMOSPHERE WILL CONTINUE TO REMAIN STABLE...SO LITTLE IF ANY STORMS ARE EXPECTED THERE. A WEAK BOUNDARY ACROSS EASTERN PORTIONS OF DOUGLAS AND ELBERT COUNTIES MAY PROVIDE SOME ADDITIONAL FOCUS FOR STORMS BY MID AFTERNOON. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE CHANCE FOR THUNDERSTORMS WILL GO WAY DOWN THIS WEEKEND... PARTICULARLY EAST OF THE MOUNTAINS...WHERE A HOT AND DRY HIGH PRESSURE SYSTEM WILL SEND AFTERNOON TEMPERATURES INTO THE MID AND UPPER 90S. BY MONDAY MONSOON MOISTURE WILL GRADUALLY RETURN TO THE OUTLOOK AREA RESULTING IN SLIGHTLY COOLER TEMPERATURES AND A BETTER CHANCE FOR THUNDERSTORMS BY LATE IN THE DAY. THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE ON TUESDAY AND WEDNESDAY WITH THE MONSOON MOISTURE PLUME OVER THE REGION AND WITH A COUPLE WEATHER DISTURBANCES PASSING BY. HEAVY RAINFALL FROM SLOW MOVING STORMS ON TUESDAY AND WEDNESDAY COULD POTENTIALLY CAUSE FLASH FLOODING IN AREAS OVER AND ALONG THE FRONT RANGE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. ENTREKIN/BAKER
The Denver radar (KFTG), 84 km away, was scanning. The volume nearest the first event began at 22:31 UTC.
1 flash flood. Local standard time, as filed.
Heavy rain produced flash flooding in the Hayman burn scar.
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, July 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: 339303.