Big Lost River near Arco water level

Name: Big Lost River near Arco water level (U.S. Geological Survey)
Creator: U.S. Geological Survey
License: https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits

River gauge, Big Lost River, Idaho, United States

Directions

Below flood stage

Water level

2.00ft Steady over the last 24 hours

Measured Oct 18, 2026, 10:00 PM MDT (42 min ago)

Flow: 0.0 cfs

History

7 days

Water level Minor flood stage

What this means

The Big Lost River near Arco is at 2.00 ft, in the normal range.

It is 4.50 ft below the flood stage of 6.50 ft.

The level has held steady over the past 24 hours. In the last month it has stayed between 2.00 ft and 2.01 ft.

Fall is often low-water season on rivers, until steadier rain returns.

Judged against the official flood stage for this gauge. How to read levels

Key numbers

Highest on record: 7.68 ftJuly 5, 1967

Floating and fishing near Big Lost River near Arco

Normal flows mean predictable rapids and good access at most put-ins.

Flood stage here is 6.50 ft, 4.50 ft above the current reading. Beyond it, the National Weather Service also defines moderate and major flood stages.

What happens at each level

6.50 ft: Widespread lowland flooding probable from Darlington/Moore areas downriver to the INL Complex boundary. Bank erosion possible. Bridges along US HWY 93 may have water near their base.
5.50 ft: Big Lost River within 1 foot of bankfull in many locations between Darlington/Moore areas to the INL Complex boundary. Some minor lowland flooding and ponding of water may occur. Isolated erosion possible along James Creek south of the Moore bridge.
2.00 ft: Right now

Impact statements from the U.S. National Weather Service.

Highest crests on record

Rank	Level	Date
1	7.68 ft	July 5, 1967
2	7.32 ft	July 12, 1983
3	7.26 ft	June 9, 1986
4	7.10 ft	June 14, 1997
5	6.86 ft	July 2, 1982
6	6.61 ft	June 23, 1974
7	6.59 ft	June 1, 1958
8	6.54 ft	June 30, 1971
9	6.53 ft	June 22, 1984
10	6.47 ft	April 7, 1969

Weather at the gauge

No rain in the last 3 days.

17 Sat 64° 30° – Wind 8 mph

18 Sun 65° 33° – Wind 8 mph

19 Mon 62° 34° – Wind 7 mph

20 Tue 63° 51° 0.03 in Wind 11 mph

21 Wed 66° 48° 0.01 in Wind 13 mph

22 Thu 65° 50° 0.04 in, 66% Wind 14 mph

23 Fri 51° 42° 0.32 in, 66% Wind 16 mph

Forecast: Open-Meteo

Sunrise 07:53 AM Sunset 06:45 PM Daylight 10 hr, 52 min First quarter 56%

Map

Other gauges on the Big Lost River

Gauge	Level	Compared with normal	24 hours	Distance
Big Lost River at Howell Ranch near ChillyRiver gauge, Big Lost River	1.00 ft	Below flood stage	±0	47 mi
Big Lost River below Mackay Reservoir near MackayRiver gauge, Big Lost River	1.67 ft	Below flood stage	±0	31 mi
Big Lost River near LeslieRiver gauge, Big Lost River	77.9 cfs	Low	−7.9 cfs	22 mi
Big Lost River below Moore Diversion near MooreRiver gauge, Big Lost River	0.0 cfs	Low	±0	15 mi
Big Lost River at Arco at Sunset RoadRiver gauge, Big Lost River	0.0 cfs	Normal	±0	4.8 mi

Nearby gauges

Gauge	Level	Compared with normal	24 hours	Distance
Antelope Creek near DarlingtonRiver gauge, Antelope Creek	4.60 ft	Below flood stage	+0.01 ft	16 mi
Little Lost River near HoweRiver gauge, Little Lost River	2.72 ft	Below flood stage	+0.01 ft	22 mi
Little Lost River above Flood Diversion near HoweRiver gauge, Little Lost River	36.1 cfs	Low	±0	23 mi
Lower Cedar Creek above Divs near MackayRiver gauge, Lower Cedar Creek	10.8 cfs	Normal	±0	31 mi
Warm Springs Creek below Diversion near MackayRiver gauge, Warm Springs Creek	43.4 cfs	High	+2.6 cfs	38 mi
Little Lost River below Wet Creek near HoweRiver gauge, Little Lost River	1.14 ft	Below flood stage	−0.01 ft	38 mi

Questions and answers

What is flood stage for the Big Lost River near Arco?

The official flood stage is 6.50 ft. The level is currently 4.50 ft below it.

Is gage height the same as water depth?

No. Gage height is measured from a fixed reference point chosen by the agency, so a reading of 10 ft does not mean the river is 10 ft deep.

What is the water level of Big Lost River near Arco today?

On Oct 18, 2026, 10:00 PM MDT, the water level was 2.00 ft. Steady over the last 24 hours.

Is Big Lost River near Arco rising or falling?

Steady over the last 24 hours.

Is the level of Big Lost River near Arco normal?

Below flood stage. Judged against the official flood stage for this gauge.

What is the highest water level ever recorded at Big Lost River near Arco?

The highest level on record is 7.68 ft on July 5, 1967.

How often is this data updated?

The U.S. Geological Survey publishes a new reading every 15 minutes. This page refreshes within minutes of each update.

For specialists

Station codes, datum, parameters, data quality and downloads

Operator: U.S. Geological Survey
Station code: usgs:13132500 (Agency page)
Coordinates: 43.58222, -113.27056 (WGS84)
Vertical datum: NAVD88
Update interval: every 15 minutes
Licence: Public domain. Data: U.S. Geological Survey (USGS), provisional data subject to revision

Published series

Parameter	Last value	Time (UTC)	Quality
Water level	2.00 ft	2026-10-19 04:00	Provisional
Flow	0.0 cfs	2026-10-19 04:00	Provisional

Download

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How to cite

U.S. Geological Survey: Big Lost River near Arco (usgs:13132500). Accessed October 19, 2026 via Nivelmap, https://nivelmap.com/en/united-states/idaho/big-lost-river-near-arco

How we check values

Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.

Readings are provisional, can be delayed or wrong and are not a flood warning. Read the disclaimer