Silver Bow County
Population 36,118 (2025) 718 sq mi
Property owners in Silver Bow County have filed 10 federal flood insurance claims since 1978, 25th most of 56 counties in Montana.
Hazard fingerprint Each spoke is this county’s percentile among U.S. counties where that hazard occurs. How it is computed
At a glance
The record for Silver Bow County in eight numbers. Each links to its section below.
Tornadoes
No tornado is recorded here in the Storm Prediction Center database, which begins in 1950.
Hurricanes and tropical storms
No tropical storm or hurricane has tracked within 100 miles since records began in 1851.
Wildfire and smoke
No large wildfire has been mapped here since satellite mapping began in 1984.
Smoke overhead
Smokiest year
2021: 63 days
Heavy smoke on 42 days in 2021, the most of any year.
Last 10 years
28.0 days a year
Medium or heavy smoke, 2016 to 2025.
2025
13 days
Medium or heavy smoke. 30 so far in 2026.
- A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.
NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.
Floods and flood insurance
10 federal flood insurance claims since 1997, with $8,245 paid.
Most claims in one year
2011: 5 claims
$5,419 paid.
Claims by ZIP code
| 59701 | 9 | $8,245 |
Flood events since 1996
- Flash Flood6
- Heavy Rain4
- Flood2
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.
River crests
Most severe crest
February 19, 1995
Blacktail Creek at Butte, 5.28 ft
0.98 feet above the 4.3 ft flood stage; minor flooding by today’s categories.
| Feb 19, 1995 | Blacktail Creek at Butte | 5.28 | +0.98 |
| Jul 6, 1994 | Blacktail Creek at Butte | 4.64 | +0.34 |
| Mar 13, 2003 | Blacktail Creek at Butte | 4.54 | +0.24 |
| Feb 8, 1996 | Blacktail Creek at Butte | 4.31 | +0.01 |
| Jun 9, 2011 | Blacktail Creek at Butte | 4.30 | 0.00 |
| Mar 20, 1997 | Blacktail Creek at Butte | 4.20 | −0.10 |
| Jul 30, 1998 | Blacktail Creek at Butte | 4.16 | −0.14 |
| Jun 12, 2017 | Blacktail Creek at Butte | 3.16 | −1.14 |
| Jul 31, 2025 | Blacktail Creek above Grove Gulch at Butte | 7.42 | −1.28 |
| Jun 8, 2020 | Blacktail Creek above Grove Gulch at Butte | 6.57 | −2.13 |
| Jun 8, 2022 | Blacktail Creek above Grove Gulch at Butte | 5.98 | −2.72 |
River gauges
| Blacktail Creek above Grove Gulch at Butte | 8.7 | 7.42 ft | 0 |
| Blacktail Creek at Butte | 4.3 | 5.28 ft | 0 |
- Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.
NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.
Drought
In severe drought or worse for 267 of 1,581 months since 1895 (17%); the longest spell lasted 59 months.
267
Months in severe drought or worse since 1895
156
Months in extreme drought
17%
Share of all months, severe or worse
Lowest reading
August 1934
−7.16, extreme drought
Longest severe spell
59 months
June 1933 to April 1938.
Latest month
September 2026
−2.69, moderate drought
Last severe month: May 2026.
- The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.
NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.
Earthquakes
42 earthquakes of magnitude 4 or more within 50 miles since 1900; the largest was magnitude 6.6 in 1925.
3
Magnitude 2.5+ inside the county since 1973
287
Magnitude 3+ within 50 miles since 1973
42
Magnitude 4+ within 50 miles since 1900
13
Magnitude 5+ within 50 miles since 1900
Largest within 50 miles
June 27, 1925
The 1925 Clarkston Valley, Montana Earthquake; 39.9 miles away.
Most recent, magnitude 3 or more
April 26, 2026
Magnitude 3.0
16 km ESE of Butte, Montana; 5.9 miles away.
Every earthquake of magnitude 4 or more within 50 miles
| Oct 7, 2024 | 4.1 | 29.2 |
| Aug 15, 2019 | 4.2 | 40.9 |
| Aug 5, 2019 | 4.1 | 41.1 |
| Jul 13, 2019 | 4.0 | 46.3 |
| Jul 17, 2017 | 4.0 | 48.9 |
| Jul 6, 2017 | 4.4 | 46.5 |
| Jul 6, 2017 | 4.0 | 45.3 |
| Jul 6, 2017 | 5.0 | 44.1 |
| Jul 6, 2017 | 5.8 | 48.3 |
| Sep 3, 2016 | 4.0 | 3.5 |
| Mar 6, 2009 | 4.0 | 4.4 |
| May 8, 2007 | 4.4 | 24.7 |
| Jun 17, 2006 | 4.1 | 17.2 |
| Jan 18, 2006 | 4.0 | 20.2 |
| Jul 27, 2005 | 4.0 | 17.4 |
| Jul 25, 2005 | 5.6 | 18.3 |
| Jun 28, 2000 | 4.0 | 49.4 |
| Oct 27, 1998 | 4.3 | 4.3 |
| Aug 7, 1989 | 4.0 | 44.6 |
| Jul 21, 1987 | 4.0 | 28.2 |
| Dec 31, 1983 | 4.0 | 42.3 |
| Mar 10, 1980 | 4.0 | 26.4 |
| Jun 22, 1979 | 4.4 | 22.0 |
| Aug 26, 1977 | 4.5 | 29.6 |
| Mar 10, 1977 | 4.6 | 42.7 |
| Feb 7, 1975 | 4.0 | 43.1 |
| Jul 16, 1974 | 4.4 | 40.1 |
| Nov 1, 1972 | 4.2 | 43.2 |
| Mar 7, 1966 | 4.8 | 48.4 |
| May 28, 1958 | 4.4 | 27.3 |
| Nov 28, 1935 | 5.0 | 37.5 |
| Oct 31, 1935 | 5.9 | 39.9 |
| Oct 18, 1935 | 6.1 | 49.5 |
| Oct 12, 1935 | 5.9 | 37.5 |
| Feb 15, 1929 | 4.7 | 49.2 |
| Feb 29, 1928 | 4.9 | 32.5 |
| Jul 10, 1925 | 5.5 | 39.9 |
| Jun 27, 1925 | 5.5 | 39.9 |
| Jun 27, 1925 | 5.5 | 39.9 |
| Jun 27, 1925 | 6.4 | 39.9 |
| Jun 27, 1925 | 6.6 | 39.9 |
| Apr 19, 1910 | 5.4 | Inside |
- Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
- Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).
USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.
Severe weather and other events
133 events in the National Weather Service record, 112 of them since 1996.
33
Hail reports, 1 inch or larger
3
Hail, 2 inches or larger
21
Damaging gusts, 58 mph+
38
Winter weather events since 1996
0
Heat events since 1996
2
Cold events since 1996
Largest hail
August 6, 2009
2.50 inches
Strongest measured or estimated gust
August 24, 1981
75 mph
Costliest events since 1996
- Dec 29, 2004Heavy Snow, Butte / Pintlar Region$85,000
National Weather Service narrative
Heavy snow event across southwest Montana brought snow amounts ranging from 5 to 8 inches in the valleys to a foot over higher mountains. The city of Anaconda received a record breaking 5.9 inches for December 30th. The previous record was 5 inches set in 1977. The Montana Highway Patrol reported several severe accidents while at least 20 cars slid off roads from snow packed and icy roads. A truck driver totaled his $85,000 truck when he struck a vehicle in front of him who lost control and slowed down. His truck skidded sideways and rolled into a ditch.
- Aug 6, 2009Hail$50,000
National Weather Service narrative
Extensive hail damage to homes, roofs, and vehicles reported on Green Acres and Continental Drive near Butte. Hail size ranged between 1.75 and two inches in diameter. In addition, wind gusts were estimated up to 70 mph, which caused some tree branches to break.
- Jun 6, 2023Flash Flood$15,000
National Weather Service narrative
The Bert Mooney Airport recorded 1.65 inches of rain in an hour. The 911 dispatch reported manholes being blown from deep water rushing down the streets, a motorhome was pushed into a ditch, and there were multiple reports of water in people's homes.
- Jun 16, 2005Hail$5,000
National Weather Service narrative
Strong thunderstorms moved through Anaconda and Rocker areas, with large hail up to golf ball size reported in each location. A weather spotter reported hail damage to cars in Rocker.
- Aug 1, 2013Thunderstorm Wind$5,000
National Weather Service narrative
The Bert Mooney airport located four miles south-southeast of Butte reported a strong west wind gust of 53 mph due to a thunderstorm that moved through. Power companies reported six utility poles on a 50K transmission line down due to the storms in southwest Montana. This caused power outages in Silver Bow county that lasted through the night. The strong winds also caused downed trees in the Butte area.
- Aug 6, 2009Hail$5,000
National Weather Service narrative
A trained spotter reported that the hail caused damage to the windows of his home as well as three vehicles. Tree branches were stripped from the large hail.
- Jul 23, 2015Thunderstorm Wind$5,000
National Weather Service narrative
A tree fell on a house bringing damage to a power box. Another large tree fell and downed multiple power poles. The power outage affected 5000 homes.
- May 13, 2026Thunderstorm Wind$2,000
National Weather Service narrative
An initial thunderstorm produced a 54 MPH wind gust just west of Homestake Pass at 1254MST. This gust resulted in a power outage that lasted until 1930MST. Later, at 1629MST, a 67 MPH wind gust was measured at the Bert Mooney Airport (KBTM). This severe gust was associated with a weak thunderstorm that mixed down stronger winds from aloft, aided by evaporative cooling. The strong winds caused a tree branch to fall onto a car.
- Mar 19, 2017Flood$1,000
National Weather Service narrative
An ice jam on the Big Hole River at the Dickie Bridge caused water to back up and flood a land owner to the west of the bridge.
- Aug 6, 2009Flash Flood$1,000
National Weather Service narrative
Flooding was reported on both Elm and Silverbow Street. A few homes on Silverbow had flooding in their basements. The Butte Plaza Mall parking lot was flooded, and strong winds caused water to flow into the doorways and walkways of the mall.
- Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.
NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.
Weather records
From Butte Bert Mooney Airport, 2 miles from the county’s population centre, with records from 1894.
- All-time high
- 100°FJul 22, 1931
- All-time low
- −52°F2 times, most recently Dec 23, 1983
- Warmest night
- 75°FJul 12, 1897
- Coldest day
- −25°FJan 21, 1962
- Wettest day
- 3.00 in2 times, most recently Jun 9, 1913
- Snowiest day
- 30.0 inOct 10, 1911
- Hottest year
- 1925mean 44.9°F
- Coldest year
- 1975mean 34.1°F
- Wettest year
- 190920.55 in
- Driest year
- 20216.49 in
Station Butte Bert Mooney Airport (USW00024135), 5,505 ft elevation, 2.0 miles from the population centre. Daily records from 1894 to October 26, 2026; 96.5% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.
NOAA NCEI Global Historical Climatology Network Daily.
Federal disaster declarations
7 since 1953. The most recent: Covid-19 Pandemic, March 31, 2020.
| Mar 31, 2020 | Biological | DR-4508-MT |
| Mar 13, 2020 | Biological | EM-3476-MT |
| Sep 13, 2005 | Hurricane | EM-3253-MT |
| Aug 30, 2000 | Fire | DR-1340-MT |
| Aug 5, 2000 | Fire | FM-2317-MT |
| Feb 23, 1996 | Severe Storm | DR-1105-MT |
| May 27, 1981 | Flood | DR-640-MT |
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.
How this compares
Where Silver Bow County stands among 56 counties in Montana and 3,143 in the United States.
| Tornadoes since 1950 | 0 | — |
| Tornadoes rated F3/EF3 or stronger | 0 | — |
| Tropical cyclones within 50 mi | 0 | — |
| Hurricane-strength passes within 50 mi | 0 | — |
| Wildfire acres since 1984 | 0 | — |
| Flood insurance claims | 10 | 25 / 56 |
| Flood insurance paid | $8,245 | 39 / 56 |
| Disaster declarations | 7 | 50 / 56 |
| Flood events since 1996 | 12 | 47 / 56 |
| Hail and wind events since 1996 | 59 | 54 / 56 |
| Winter storm events since 1996 | 38 | 54 / 56 |
| Reported damage since 1996 | $175,000 | 48 / 56 |
| River crests at major flood stage | 0 | — |
| High tide flooding days a year, last 10 years | 0.0 | — |
| Months in severe drought since 1895 | 267 | 5 / 56 |
| Medium or heavy smoke days a year, last 10 years | 28.0 | 42 / 56 |
| Earthquakes M4+ within 50 mi since 1900 | 42 | 9 / 56 |
| Earthquakes M2.5+ in the county since 1973 | 3 | 22 / 56 |
Neighbouring counties
| Beaverhead County | 14 | 0 |
| Deer Lodge County | 1 | 0 |
| Jefferson County | 1 | 0 |
| Madison County | 2 | 0 |
Sources and vintage
Every number on this page comes from these public records.
- Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
- Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
- Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
- Storm events NOAA NCEI Storm Events Database, through 2026.
- Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
- Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
- Weather records NOAA NCEI Global Historical Climatology Network Daily, station USW00024135.
- River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
- Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
- Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
- Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.
Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.