Niobrara County, Wyoming

What hazards hit Niobrara County most?

The most frequent records are hail reports: 217 since 1965. 69% of its hail reports since 1965 fell in June and July. The rank column places the county among Wyoming's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Niobrara County had?

NOAA records 36 tornadoes in Niobrara County from 1950 to 2025, the strongest rated F2, with 0 deaths and 5 injuries recorded in the county. That is 5th of 23 Wyoming counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 36 tornadoes whose track touched Niobrara County since 1950 (NOAA's county records number 36, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in Wyoming.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Niobrara County?

The most recent record with damage, injuries or deaths is the June 4, 2015 flash flood ($1.9 million in damage in 2025 dollars).

As much as eight inches of rain fell from slow moving thunderstorms across south and southeast Niobrara County during the predawn hours, which resulted in widespread flash flooding. Excessive runoff upstream into the Niobrara River and nearby creeks caused them to overflow their banks. Law enforcement officials evacuated residents of Lusk as well as those living along the Niobrara River downstream to Van Tassel several hours in advance of the flood wave. The worst damage occurred in Lusk where 20 to 30 homes and 15 to 20 businesses were destroyed. Flood waters and debris rushed down Main Street in Lusk, swamped four blocks, and shut down the town's water supply. The US Highway 85 bridge on the north side of Lusk collapsed onto the railroad tracks below. …
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 589431)

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Niobrara County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Winter storms in the 2010s: 65 records against 16 in the decade before, 65 of them forecast-zone records. Cells marked z rose mostly through zone records. The local National Weather Service office files these once per forecast zone, so a change in how it draws its zones or splits a storm into records moves this count as much as the weather does; read it beside the Niobrara County days with a record above.

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

69% of its hail reports since 1965 fell in June and July. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for Niobrara County

FEMA's register lists 5 declarations that include Niobrara County: 4 major disasters, one emergency and 0 fire management assistance declarations. Most were for biological (2) and flood (2).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Niobrara County had?

NOAA's Storm Events Database holds 5 flood or flash flood records for Niobrara County from 2006 to 2023, on 5 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Niobrara County ranks 2830th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $570 on 1 claim filed in Niobrara County; the most in one year was 1 in 2000. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Niobrara County

FEMA's National Risk Index rates Niobrara County Very Low overall, with an expected annual loss of $1.8 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Niobrara County

1. Platte County 1,842
2. Custer County, SD 1,466
3. Fall River County, SD 1,001
4. Goshen County 959
5. Weston County 911
6. Converse County 843
7. Sioux County, NE 594
8. Niobrara County 489

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in WyomingEvery Wyoming tornado since 1950 and the counties with the most per square mile
• Hail in WyomingThe state's hail reports, by county, year and month
• The Wyoming recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Niobrara CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Niobrara County's FEMA declarations (CSV)5 rows: every declaration that named the county, for your own analysis