Strong thunderstorms over central and southern Utah produced flash flooding during the second week of July.
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 SLC wrote it up.
Strong thunderstorms over central and southern Utah produced flash flooding during the second week of July.
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 9, 7:56 AM MST, 6 hours 34 minutes earlier.
Area Forecast Discussion National Weather Service Salt Lake City UT 856 AM MDT Mon Jul 9 2018 .SYNOPSIS...A ridge of high pressure will remain over much of the southwestern United States through the week. Deep monsoonal moisture will persist across Utah through at least the first half of the week. && .DISCUSSION...Upper level ridging remains centered east of Utah this morning, with a light but generally southerly flow pushing moisture into the Great Basin from the south. Another fairly warm night was observed statewide, including low temps of 74 at Salt Lake City and 84 at the St. George airport. With no real synoptic scale forcing to speak of, most of the shower activity died off overnight, but should get going again after 16-18Z as usual. Today is largely expected to be a repeat of yesterday, with convection staying relatively tied to the terrain early in the afternoon, then drifting off through the latter half of the afternoon into the evening. A couple of differences from yesterday may include more activity further north, potentially including places such as Rich/Cache counties, and a slightly unusual east- to- west drifting of some storms, especially in the southern half of the state. As has been the case since this airmass moved over the area, isolated flash flooding is possible today if storms move over some of the flood prone areas. The threat of gusty winds is generally less than yesterday, though not out of the question, especially in the far north. The forecast for today looks to be in good shape and no updates are currently planned for the morning. && .AVIATION...Southeasterly surface winds at the SLC terminal should switch to the northwest between 19-20z. Showers and storms are expected to once again develop in the vicinity of the terminal this afternoon, with a 60% chance of gusty southerly outflow winds in the 21-03z timeframe. && .FIRE WEATHER...The monsoonal moisture has spread across the entire region with the deepest moisture across southern and central Utah. Terrain will be the main driving force for thunderstorms and showers today with isolated heavy rain possible. Relative humidity values are expected to remain elevated through this week except across the north where a drying trend will set in late in the work week and then work its way southward for the weekend. Temperatures will vary little from day-to-day due to being tied closely to the amount of sunshine. Other than outflow winds across the north yet today, winds in general will be light through this week. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && PUBLIC...Schoening AVIATION...Verzella FIRE WEATHER...Struthwolf For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity For frequently asked questions about the Area Forecast Discussion visit... http://weather.gov/saltlakecity/general/afd_faqs.php
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
258 PM MDT MON JUL 9 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0244 PM FLASH FLOOD 4 N BRIAN HEAD 37.76N 112.84W
07/09/2018 IRON UT DEPT OF HIGHWAYS
STATE ROUTE 143 CLOSED DUE TO WATER OVER ROADWAY.
&&
LCSpecial Weather Statement National Weather Service Salt Lake City UT 328 PM MDT MON JUL 9 2018 UTZ006-009-010-092215- Wasatch Mountain Valleys UT-Wasatch Plateau/Book Cliffs UT- Western Uinta Mountains UT- 328 PM MDT MON JUL 9 2018 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN WASATCH AND SOUTH CENTRAL SUMMIT COUNTIES UNTIL 415 PM MDT... At 327 PM MDT, National Weather Service Doppler radar indicated a strong thunderstorm near Timber Lakes, or 13 miles east of Heber City...moving northeast at 15 mph. Nickel size hail and winds in excess of 40 mph will be possible. Locations impacted include... Timber Lakes, Samak, Woodland and Trial Lk. PRECAUTIONARY/PREPAREDNESS ACTIONS... If threatening weather approaches, take shelter in a sturdy building. && LAT...LON 4033 11116 4040 11136 4080 11111 4070 11092 TIME...MOT...LOC 2127Z 207DEG 11KT 4050 11115 DSB
The Cedar City radar (KICX), 19 km away, was scanning. The volume nearest the first event began at 21:27 UTC.
10 flash flood. Local standard time, as filed.
The Utah Department of Transportation reported a debris flow after heavy rain fell over the Brianhead Fire burn scar. The flood waters temporarily closed State Route 143.
Heavy rain on the Brianhead Fire burn scar produced two debris flows that temporarily closed State Route 143.
Heavy rain over Zion National Park produced the largest flash flood at the park since 2011, with the flow volume of the North Fork of the Virgin River increasing to 200 times its normal value. The Zion-Mount Carmel Highway through the park was temporarily closed due to rocks and debris on the road, stranding some vehicles. The rain also caused an extended closure of the Angels Landing, Upper Emerald Pools, and Kayenta Trails. No injuries were reported.
Flash flooding occurred along the Paria river, with the river gauge on the Paria rising from 0 cfs to 952 cfs in one hour.
Heavy rain resulted in a small flash flood in Zion National Park that closed the upper road to Temple of Sinawaba due to minor debris.
Heavy rain over Washington County resulted in a flash flood that damaged 20 homes in Dammeron Valley, three in Hurricane, and two in Washington. State Route 18 was temporarily closed due to debris on the road.
Heavy rain fell on the Black Mountain Fire burn scar, resulting in a debris flow that temporarily closed State Route 130 near Minersville.
State Route 143 was temporarily closed after heavy rain over the Brianhead Fire burn scar resulted in a debris flow that moved over the road.
Heavy rain produced a large flash flood in Warm Creek and Last Chance Creek.
Heavy rain fell in the city of Washington, flooding approximately six homes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2018Every state in 2018This day in weather historyWarnings in Utah, July 2018
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: 771343, 771344, 771372, 771373, 771654, 771658, 771655, 771670, 771684, 771661.