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FEMA flood zones · Idaho

Butte County, Idaho Flood Zone Map

1 federal flood & hurricane disasters

FEMA’s digital flood map shows no high- or moderate-risk zones in Butte County. That can mean the area was never studied in detail or has no digital map, not that it can’t flood; the county floodplain administrator can say which.

Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.

Coastal high risk (V, VE)FloodwayHigh risk (A, AE)Moderate (X, 500-year)Minimal (X)Undetermined (D)

Shaded areas are FEMA’s mapped flood hazard zones in and around Butte County, Idaho. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.

In their words

3 NOAA storm reports from Butte County describe what happened, in the words of the forecasters who covered it. Read the Idaho flood stories →

Federal disasters

6 federal disaster declarations since 1964, 1 of them floods, coastal storms or hurricanes.

DisasterBegan
Hurricane KatrinaAug 29, 2005
Severe Storms, Snowmelt, Land/mud Slides, FloodingMar 14, 1997
EarthquakeOct 28, 1983
Heavy Rains & FloodingDec 31, 1964

Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.

Recorded flood events

11 since 1996: 3 flash floods and 8 river or area floods.

EventDateDamage
FloodJan 14, 2019—
FloodJan 9, 2019—
FloodMar 13, 2018$75,000
FloodJan 9, 2017—
FloodFeb 4, 2017$265,000
FloodMay 1, 2017$45,000
FloodMar 1, 2017$135,000
FloodJun 1, 2017$10,000

— = no damage estimate in the record. Source: NOAA Storm Events Database.

From the storm reports

Flood · Jan 14, 2019. Flooding returned south of Moore due to ice jamming of the Big Lost River on the 14th. Only farm land was flooded.

Flood · Jan 9, 2019. Some property and farmland flooding occurred south of Moore in Butte County on January 9th along the Big Lost River. A land owner rescued his cattle from the flooding with none lost due to the flood. Hay storage was also safely relocated.

Flood · Mar 13, 2018. A return to heavy mountain snows in late February and early March added significantly to the snow pack especially in the Upper Snake River Highlands and snow melt and heavy rains occurred sporadically from the middle of the month onward. The worst of the flooding occurred in Clark and Madison which were both declared state disaster areas by the end of the month. Low elevations in the central mountains also beg…

Flood · Jan 9, 2017. A long dawn out atmospheric river event brought a variety of impacts to southeast Idaho including extremely heavy mountain snow, valley snow then rain on snow leading to flooding and roads covered with ice in the Snake River Plain, and many mountain avalanches. Many roads were closed for extended periods due to the heavy snow and avalanches. Custer County was declared a disaster area due to the prodigious snow…

National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.

The zones you’ll see on the map

Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.

Cross-section of a river floodplainDiagram: a river valley. The floodway is the channel and the land beside it; the 1%-annual-chance flood surface (the base flood elevation) covers the valley floor as zone A or AE; a narrow band higher up is shaded X, the 0.2% floodplain; higher ground is X.0.2% CHANCE A YEAR (500-YEAR)BASE FLOOD ELEVATION · 1% A YEARXAEFloodwayAEX
  1. A / AE Inside the 1%-a-year floodplain: about a 26% chance of flooding over a 30-year mortgage. AE has a mapped base flood elevation; plain A does not.
  2. Floodway The channel and the land beside it that has to be kept clear enough to carry the flood. Building here is tightly limited.
  3. X shaded The 0.2% (500-year) floodplain, plus some levee-protected and very shallow flood areas.
  4. X Outside both lines. No federal requirement to insure, which is not the same as no risk.

Every flood zone code explained →

Flood insurance in Butte County

If a building in Butte County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.

Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.