Rivermatics

USGS Streamgage 13120500

Big Lost River at Howell Ranch near Chilly, ID

Big Lost River at Howell Ranch near Chilly, ID is USGS streamgage 13120500 in Idaho, monitoring river discharge in hydrologic subbasin 17040218. It sits on the Big Lost River, alongside 8 other gauges Rivermatics tracks on the same river. It drains a watershed of about 440 square miles. Discharge records at this site go back to 1904. Typical flow runs near 501.5 cfs in July and 145 cfs in April, with the higher of the two arriving in July. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.

View live conditions & forecast →

Gauge details

State
Idaho
Drainage area
440 sq mi
Subbasin (HUC-8)
17040218
Coordinates
43.99833, -114.02111
USGS site number
13120500
Records begin
1904-05-01 (122 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Big Lost River at Howell Ranch near Chilly, ID. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
90.8 95.9 99.8
88.5 94.5 99.3
86.8 93.2 98.6
85.6 92.5 98.5
84.5 91.5 97.8
85.9 94 103
87.6 98.5 114
86.4 96.8 111
84.5 94.6 107
83 92.8 104
81.6 91.4 102
80.4 90.3 100
79.4 89.4 99.6
78 88.4 98.7

All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 122 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 56 78 106.9
February 52.5 74.9 99.2
March 55.7 77 117.5
April 75.8 145 360.5
May 280.1 644.5 1,403.5
June 433.3 1,068.7 2,118
July 178 501.5 1,047.7
August 85.7 182 341.5
September 70.8 128.2 216.1
October 71.6 117.8 183.3
November 65.9 98.7 141.4
December 57.1 82.2 115.8

All values in cubic feet per second (cfs).

Common questions

When does Big Lost River at Howell Ranch near Chilly, ID normally run highest?
June, on the long-term record. The median daily flow that month is about 1,068.7 cfs, against 74.9 cfs in February, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Big Lost River at Howell Ranch near Chilly, ID?
It depends on the month. In January, half of days historically fall near 78 cfs, with the middle 80% of days between 56 and 106.9 cfs. The month-by-month table on this page gives the full range.
How long has Big Lost River at Howell Ranch near Chilly, ID been measured?
Discharge records at USGS site 13120500 begin in 1904, about 122 years, covering roughly 9,200 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Big Lost River at Howell Ranch near Chilly, ID?
Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
Where is Big Lost River at Howell Ranch near Chilly, ID?
The gauge sits at 43.99833, -114.02111, in Idaho, in hydrologic subbasin 17040218, draining roughly 440 square miles.
Can I use Big Lost River at Howell Ranch near Chilly, ID data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Upstream and downstream on the Big Lost River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Big Lost River in full.

Other gauges in this subbasin