The lightning-caused fire started on July 17th in the northeast Crazy Mountains, 24 miles southwest of Harlowton. Driven by an unusual east wind, the fire made a significant run to the west late on July 30th but was stopped short of homes and other structures in the Shields River area.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 BYZ wrote it up.
The lightning-caused fire started on July 17th in the northeast Crazy Mountains, 24 miles southwest of Harlowton. Driven by an unusual east wind, the fire made a significant run to the west late on July 30th but was stopped short of homes and other structures in the Shields River area. Total personnel on the fire was around 100 with 21,892 acres burned. Fuels involved were short grass and timber but primarily mixed conifer with timber liter and understory fuels. For more information, please see the latest GACC (Geographic Area Coordination Center) Detailed Situation Report.
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 Billings, MT wrote its last area forecast discussion before the first event at Jul 31, 1:26 PM MST, 10 hours 34 minutes earlier.
Area Forecast Discussion
National Weather Service Billings MT
226 PM MDT Sat Jul 31 2021
.DISCUSSION...
Tonight through Monday night...
Upper level ridge along the spine of the Rockies infused with with
monsoon moisture getting beaten down a bit as a shortwave moves
from eastern Oregon into western Montana Sunday into Monday. This
gradually pushes deeper monsoon moisture into the western Mountain
ranges Sunday and a bit further east Monday including the western
Foothills and lower elevations from Billings westward.
Throughout the area temperatures will remain hot and surface
winds will remain easterly Sunday as a surface trough lays just to
the east of the ridge axis. By Monday this trough moves into the
plains and winds become lighter.
Bigger question is precipitation amounts with models progressively
restricting decent rainfall to the high country where terrain has
a chance to initiate convection. At this point best chances seem
to be restricted to elevations above 7000 feet in the Beartooth
and Absaroka and Crazy Mountains. borsum
Tuesday through Saturday...
An upper level shortwave trough will continue to move across the
forecast area Tuesday resulting in continued chances for showers
and thunderstorms. Any thunderstorm looks to be wet and slow-
moving as precipitable waters will be in the 1.00"-1.25" range.
As a result, any thunderstorms that do develop will be capable of
producing heavy rain. The upper shortwave trough will move
eastward into the Dakotas on Wednesday and weak upper ridging will
move over our area. Shower and thunderstorm potential looks more
limited on Wednesday, confined mainly to the mountains and
adjacent foothills.
However, Thursday into early next weekend, a stronger upper low
and trough approach from the Pacific northwest resulting in a
southwest flow aloft. This could be a good set-up for severe
thunderstorms. This system will also bring a strong Pacific front
across the forecast area Thursday night into Friday. Winds along
and behind the front could possibly be strong. As a result,
Thursday and Friday will need to be watched closely for fire
weather concerns. High temperatures will generally be in the 80s
and 90s through the period. Hooley
&&
.AVIATION...
Scattered showers and thunderstorms are expected over and near
the mountains this afternoon through this evening. VFR conditions
will prevail across the forecast area. However, MVFR conditions
will be likely in and near any thunderstorm activity. Otherwise,
expect hazy conditions through tonight. Smoke aloft will continue
to reduce slant range visibility. Some locations may also see
surface visibility reduced to MVFR conditions at times due to
smoke. Hooley
&&
.PRELIMINARY POINT TEMP/POPS...
Sun Mon Tue Wed Thu Fri Sat
-----------------------------------------------------------
BIL 065/095 066/094 068/088 063/095 063/096 063/088 059/090
00/H 13/W 34/T 11/U 12/T 21/B 11/U
LVM 058/092 059/089 058/085 055/092 055/090 054/084 050/087
12/T 37/T 74/T 12/T 23/T 21/B 11/U
HDN 062/096 061/097 064/090 061/096 059/098 060/091 056/091
00/H 01/B 23/T 21/U 12/T 21/B 11/U
MLS 062/093 061/095 066/094 066/096 064/097 066/092 062/088
00/H 00/B 12/T 21/U 12/T 21/B 10/U
4BQ 061/091 061/094 065/092 066/093 064/096 066/092 061/089
00/H 00/U 12/T 21/U 12/T 21/U 10/U
BHK 058/091 057/092 061/094 064/094 062/096 064/092 059/087
00/H 00/H 11/B 21/B 12/T 31/B 10/U
SHR 056/091 058/094 060/086 057/091 057/094 058/090 054/089
10/H 01/U 24/T 32/T 12/T 21/U 01/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
weather.gov/billingsThe national radar mosaic for the moment the first event began.
2 wildfire. Local standard time, as filed.
Please see Episode Narrative.
Please see Episode Narrative.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2021Every state in 2021This day in weather historyWarnings in Montana, August 2021
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: 978909, 978910.