Flash Flood, Utah
- When
- July 17, 4:24 PM MST to 7:00 PM MST
- Where
- Utah County, Northwest Portion
- Property damage
- $350,000
- Reported by
- BROADCAST MEDIA
- Coordinates
- 40.120, -111.670 (the zone’s center; the record gives no point)
Flash Flood in Utah, July 17, 2004
Strong thunderstorms once again formed in a very moist environment over central Utah during the afternoon hours and moved north to the Cedar Fort area during the evening. The thunderstorms brought heavy rain to an area that experienced heavy rain and flash flooding during the previous day.
Where it happened
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.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- $350,000
- 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 happened
The episode as NWS SLC wrote it up.
Strong thunderstorms once again formed in a very moist environment over central Utah during the afternoon hours and moved north to the Cedar Fort area during the evening. The thunderstorms brought heavy rain to an area that experienced heavy rain and flash flooding during the previous day. Many homes once again reported significant damage to basements and property.
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 Salt Lake City, UT wrote its last area forecast discussion before the first event at Jul 17, 2:40 PM MST, 1 hour 44 minutes earlier.
Area forecast discussion, Jul 17, 2:40 PM MST, 1 hour 44 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 340 PM MDT SAT JUL 17 2004 .SYNOPSIS...A VERY MOIST AIRMASS AND WEAK FLOW ALOFT WILL REMAIN OVER THE AREA TONIGHT. A WESTERLY FLOW WILL DEVELOP OVER THE AREA SUNDAY AND PERSIST THROUGH THE MIDDLE OF NEXT WEEK BRINGING A SLOW DRYING TREND. && .DISCUSSION...RAPID INCREASE IN STRENGTH OF THE STRONGER THUNDERSTORMS OVER THE LAST HOUR AS WE APPROACH PEAK AFTERNOON HEATING. ALTHOUGH THE STRONG CELLS ARE SOMEWHAT ISOLATED ITS HARD TO SAY JUST WHERE THE THREAT OF HEAVY IS THE GREATEST. THE GREATEST CHANCE WILL BE IN WEST CENTRAL UT AS THE SHORTWAVE THAT WAS NEAR SGU THIS MORNING CONTINUES NORTHWARD. THIS WILL SOON INCLUDE THE SOUTHERN END OF THE WASATCH FRONT. BUT THE POTENTIAL FOR HEAVY RAIN IS STILL HIGH THROUGHOUT THE AREA. WITH ABUNDANT MOISTURE AVAILABLE AND LIGHT FLOW RESULTING IN CELL MOVEMENT GENERALLY LESS THAN 10 KTS. SO WILL LEAVE THE FLASH FLOOD WATCH OUT FOR THE WHOLE AREA THROUGH 03Z...2100MDT. ONLY A GRADUAL CHANGE OVER MUCH OF THE NEXT WEEK AS THE HIGH CONSOLIDATES OVER WESTERN NM THEN DRIFTS SLOWLY WEST THROUGH THE WEEK. THE FLOW TURNS MORE SOUTHWESTERLY BY TOMORROW THEN BRIEFLY WESTERLY MONDAY. BUT PRECIPITABLE WATER VALUES ARE SLOW TO DROP WITH THE FLOW STILL FAIRLY LIGHT. BY THE END OF THE WEEK THE HIGH IS CENTERED ON THE UT/AZ BORDER BUT THE GFS HAS STARTED INCREASING THE MOISTURE AGAIN. GFS BUFR DATA SHOWS PRECIPITABLE WATER VALUES ARE BACK AROUND 1.3-1.4 INCHES AT SGU AND 4HV BY FRIDAY AFTERNOON AND OVER AN INCH AT CDC AND BCE BY SATURDAY. HOWEVER THE PROXIMITY OF THE HIGH MAY INHIBIT ACTIVITY A BIT AND THE INCREASE IN MOISTURE STILL HIGHLY DEPENDENT ON EXACTLY NOW THE FLOW PATTERNS SET UP. SO FOR NOW WILL KEEP THE THREAT OF CONVECTION MAINLY OVER THE MOUNTAINS AND POINT PROBABILITIES STILL IN THE SLIGHT CHANCE RANGE. BUT IF THESE VALUES WORK OUT WE MAY BE GETTING SOME HEAVY STORMS AGAIN TOWARD THE END OF THE WEEK. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...FLASH FLOOD WATCH NOON UNTIL 900 PM TODAY...SEE SLCFFASLC WY...FLASH FLOOD WATCH NOON UNTIL 900 PM TODAY...SEE SLCFFASLC ID...FLASH FLOOD WATCH NOON UNTIL 900 PM TODAY...SEE SLCFFASLC && SANDERS
Hazardous weather outlook, Jul 17, 5:05 AM MST, 11 hours 19 minutes before
HAZARDOUS WEATHER OUTLOOK...COR NATIONAL WEATHER SERVICE SALT LAKE CITY UT 605 AM MDT SAT JUL 17 2004 UTZ002>021-181300- CASTLE COUNTRY-CENTRAL AND SOUTHWEST MOUNTAINS- GLEN CANYON RECREATION AREA/LAKE POWELL- GREAT SALT LAKE DESERT AND MOUNTAINS-HENRY MOUNTAINS- NORTHERN WASATCH FRONT-SALT LAKE AND TOOELE VALLEYS-SAN RAFAEL SWELL- SANPETE/SEVIER VALLEYS-SOUTH CENTRAL UTAH-SOUTHERN WASATCH FRONT- SOUTHWEST UTAH-UTAHS DIXIE AND ZION NATIONAL PARK- WASATCH MOUNTAIN VALLEYS-WASATCH MOUNTAINS I-80 NORTH- WASATCH MOUNTAINS SOUTH OF I-80-WASATCH PLATEAU/BOOK CLIFFS- WEST CENTRAL UTAH-WESTERN UINTA BASIN-WESTERN UINTA MOUNTAINS- 605 AM MDT SAT JUL 17 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO-THIRDS OF UTAH. .DAY ONE... TODAY SCATTERED SLOW MOVING THUNDERSTORMS WILL DEVELOP AGAIN TODAY. LOCAL HEAVY RAINFALL IS LIKELY. A FLASH FLOOD WATCH IS IN EFFECT FOR MOST OF THE WESTERN 2/3 OF UTAH BEGINNING AT NOON...AND CONTINUING THROUGH 900 PM THIS EVENING. SEE THE LATEST FLOOD WATCH (SLCFFASLC) FOR DETAILS. IN ADDITION...FREQUENT DEADLY LIGHTNING WILL OCCUR OVER THE MOUNTAINS. .DAYS TWO THROUGH SEVEN... SUNDAY THROUGH FRIDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
The radar
The Salt Lake City radar (KMTX), 143 km away, was scanning. The volume nearest the first event began at 23:23 UTC.
Event by event
1 flash flood. Local standard time, as filed.
What these are
- 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.
The same day elsewhere
- Lightning Strike in North Carolina, July 17, 2004
- Lightning Strike in South Carolina, July 17, 2004
- Tornadoes in North Carolina, July 17, 2004
- Wildfire in California, July 17 to 20, 2004
- Flash Flood and Damaging Wind in Louisiana, July 17, 2004
- Flash Flood in Pennsylvania, July 17, 2004
- Flash Flood in New York, July 17, 2004
- Damaging Wind in Texas, July 17, 2004
- Damaging Wind in Tennessee, July 17, 2004
- Flash Flood in North Carolina, July 17, 2004
- Damaging Wind in Tennessee, July 17, 2004
- Damaging Wind in North Carolina, July 17, 2004
More
Every storm in Utah in 2004Every state in 2004This day in weather historyWarnings in Utah, July 2004
Sources
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: 5422474.