Utah, 2004

Flash Flood in Utah, July 17, 2004

July 17, 2004 · NWS SLC · 1 event in 1 county or zone

A line of strong thunderstorms oriented from southwest to northeast moved over an area previoulsly burned by a wildfire. The line of storms droppped about three quarters of an inch of rain in 20 minutes and caused a mud flow 18-30 feet wide nad 2 feet deep to flow onto a forest service fire road.

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.

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  • Floods
  • Wind
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  • Cold
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The toll

Deaths
0
Injuries
0
Property damage
$1,000
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.

A line of strong thunderstorms oriented from southwest to northeast moved over an area previoulsly burned by a wildfire. The line of storms droppped about three quarters of an inch of rain in 20 minutes and caused a mud flow 18-30 feet wide nad 2 feet deep to flow onto a forest service fire road.

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, 5 hours 16 minutes earlier.

Area forecast discussion, Jul 17, 2:40 PM MST, 5 hours 16 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, 14 hours 51 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.

In the hours before

Local storm report, Jul 17, 6:10 PM MST, 1 hour 46 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
710 PM MDT SAT JUL 17 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0700 PM     FLASH FLOOD      OPHIR                   40.38N 112.29W
07/17/2004                   TOOELE             UT   TRAINED SPOTTER

            DEBRIS AND WATER ACROSS OPHIR CANYON ROAD.

&&

CVG
Local storm report, Jul 17, 7:07 PM MST, 49 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
807 PM MDT SAT JUL 17 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0700 PM     FLASH FLOOD      15 W LEHI               40.40N 112.14W
07/17/2004                   UTAH               UT   LAW ENFORCEMENT

            FLASH FLOODING IN CEDAR FORT...NORTHWEST UTAH COUNTY.

&&

CVG

The radar

The Salt Lake City radar (KMTX), 41 km away, was scanning. The volume nearest the first event began at 02:56 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Davis

When
July 17, 7:56 PM MST to 9:30 PM MST
Where
Davis County, Farmington
Property damage
$1,000
Reported by
EMERGENCY MANAGER
Coordinates
40.991, -112.111 (the zone’s center; the record gives no point)

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

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: 5422475.