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Big Lost River near Arco

Highest listed crest 7.68 ftFlood stage 6.5 ft23 crests since 1958

The Big Lost River near Arco crested above flood stage 9 times among the 23 crests the National Weather Service lists from 1958 to 2019. The highest, 7.68 ft on July 5, 1967, was minor flooding, 1.18 feet above flood stage.

The gauge

Highest listed crest
7.68 ft
July 5, 1967; 1,890 cubic feet per second
Flood stage
6.5 ft
No major stage set
Crests at major
0
9 above flood stage
Most recent flood crest
June 14, 1997
7.10 ft, minor flooding
Location
Butte County
Idaho

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Big Lost River near Arco
Action stage5.54Jun 3, 2018The level at which the NWS or its partners begin to take action
Flood stage (minor)6.59Jun 14, 1997Minimal or no property damage, but possibly some public threat

Every listed crest

23 crests from 1958 to 2019. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Big Lost River near Arco, 1958 to 2019 02468ft Flood stage 6.5 ft Jun 1, 1958: 6.59 ft, minor flooding; 1,190 cubic feet per secondJul 5, 1967: 7.68 ft, minor flooding; 1,890 cubic feet per secondApr 7, 1969: 6.47 ft, action stage; 1,180 cubic feet per secondJun 30, 1971: 6.54 ft, minor flooding; 1,220 cubic feet per secondJun 23, 1974: 6.61 ft, minor flooding; 1,260 cubic feet per secondJul 2, 1982: 6.86 ft, minor flooding; 1,430 cubic feet per secondJul 12, 1983: 7.32 ft, minor flooding; 1,820 cubic feet per secondJun 22, 1984: 6.53 ft, minor flooding; 1,300 cubic feet per secondJun 9, 1986: 7.26 ft, minor flooding; 1,860 cubic feet per secondJun 14, 1997: 7.10 ft, minor flooding; 1,750 cubic feet per secondJun 1, 2005: 4.43 ft, below flood stage; 245 cubic feet per secondJun 12, 2006: 5.62 ft, action stage; 738 cubic feet per secondJun 23, 2009: 4.73 ft, below flood stage; 388 cubic feet per secondJun 9, 2010: 4.14 ft, below flood stage; 215 cubic feet per secondJul 8, 2011: 4.46 ft, below flood stage; 286 cubic feet per secondApr 29, 2012: 4.68 ft, below flood stage; 351 cubic feet per secondJul 8, 2013: 2.57 ft, below flood stage; 10 cubic feet per secondJun 17, 2014: 2.41 ft, below flood stage; 1 cubic feet per secondJun 1, 2015: 1.99 ft, below flood stageJun 1, 2016: 1.99 ft, below flood stageJun 23, 2017: 5.87 ft, action stage; 930 cubic feet per secondJun 3, 2018: 5.70 ft, action stage; 837 cubic feet per secondJun 21, 2019: 5.00 ft, below flood stage; 520 cubic feet per second Highest, 7.68 ft, Jul 5, 1967 1960197019801990200020102020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Big Lost River near Arco 1950s: 1 1960s: 1 1970s: 2 1980s: 4 4 1990s: 1 2000s: 0 2010s: 0 1950s1960s1970s1980s1990s2000s2010s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

Highest listed crests, Big Lost River near Arco
1Jul 5, 19677.68+1.18Minor1,890
2Jul 12, 19837.32+0.82Minor1,820
3Jun 9, 19867.26+0.76Minor1,860
4Jun 14, 19977.10+0.60Minor1,750
5Jul 2, 19826.86+0.36Minor1,430
6Jun 23, 19746.61+0.11Minor1,260
7Jun 1, 19586.59+0.09Minor1,190
8Jun 30, 19716.54+0.04Minor1,220
9Jun 22, 19846.53+0.03Minor1,300
10Apr 7, 19696.47−0.03Action1,180
11Jun 23, 20175.87−0.63Action930
12Jun 3, 20185.70−0.80Action837
13Jun 12, 20065.62−0.88Action738
14Jun 21, 20195.00−1.50Below flood stage520
15Jun 23, 20094.73−1.77Below flood stage388
16Apr 29, 20124.68−1.82Below flood stage351
17Jul 8, 20114.46−2.04Below flood stage286
18Jun 1, 20054.43−2.07Below flood stage245
19Jun 9, 20104.14−2.36Below flood stage215
20Jul 8, 20132.57−3.93Below flood stage10
21Jun 17, 20142.41−4.09Below flood stage1
22Jun 1, 20151.99−4.51Below flood stage—
23Jun 1, 20161.99−4.51Below flood stage—

The worst floods along the Big Lost River

For this gauge's highest crests, the other gauges on the Big Lost River that crested above flood stage within a week.

June 9, 1986: 7.26 ft here, minor flooding

July 2, 1982: 6.86 ft here, minor flooding

Gauges on the Big Lost River

In USGS station-number order, which runs downstream within a river basin.

Flood gauges on the Big Lost River
Howell RanchID4.16.02 ft, May 25, 19670
Mackay ReservoirID4.36.08 ft, Jun 6, 19860
Arco this gaugeID6.57.68 ft, Jul 5, 19670

Other gauges in Butte County

Flood gauges in Butte County
Darlington6.06.37 ft, Jun 7, 20190
Wet Creek (Clyde)3.43.90 ft, May 10, 19660
Howe4.57.22 ft, Jun 17, 19750

Butte County: every hazard · River floods across the country · Idaho

NOAA National Water Prediction Service, gauge ARCI1, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.