The monitoring network within this area

Hydrionis holds 2,764 values from 3 gauges within it. Discharge is a property of a gauge and its reach, not of this drainage area, so this page reports the network and its records rather than a single figure.

3

Gauges

2,764

Values held

1903–2026

Record spans

Gauges within the Snake Headwaters huc8 subbasin

3 monitoring points, positioned as the publisher records them.

Flood peaks, as measured

This gauge's flood record, as measured. Unlike a daily mean it is the discharge at the moment the river was highest, which is the figure flood frequency analysis is built on.

Largest measured flow of each year at SNAKE RIVER NEAR MORAN, WY

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1904–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Published by the gauge's own operator from its sub-daily record; Hydrionis stores the figure rather than recomputing it. A year the gauge did not cover produces no value rather than a low one, and the gaps are stated below the chart. A peak is a property of this gauge and its reach: a larger flood upstream or downstream of it is not in this series.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	SNAKE RIVER NEAR MORAN, WY (m³/s)
1904	225
1905	141
1906	168
1907	209
1908	178
1909	300
1910	343
1911	275
1912	265
1913	286
1914	271
1915	272
1916	265
1917	340
1918	428
1919	331
1920	311
1921	309
1922	314
1923	303
1924	257
1925	261
1926	273
1927	402
1928	323
1929	220
1935	236
1936	166
1937	215
1938	211
1939	209
1940	231
1941	193
1942	221
1943	377
1944	240
1945	197
1946	265
1947	245
1948	248
1949	207
1950	229
1951	166
1952	218
1953	199
1954	303
1955	212
1956	177
1958	125
1959	193
1960	149
1961	178
1962	121
1963	229
1964	151
1965	138
1966	140
1967	133
1968	161
1969	126
1970	163
1971	197
1972	147
1973	130
1974	191
1975	152
1976	173
1977	142
1978	164
1979	139
1980	169
1981	323
1982	207
1983	257
1984	259
1985	215
1986	297
1987	118
1988	175
1989	131
1991	201
1992	145
1993	88.3
1994	170
1995	143
1996	260
1997	343
1998	174
1999	187
2000	166
2004	195
2005	129
2006	190
2007	131
2008	174
2009	162
2010	317
2011	239
2012	174
2013	146
2014	96.3
2015	132
2016	95.1
2017	188
2018	207
2019	133
2020	159
2021	150
2022	110
2023	69.4
2024	175
2025	112

About this series

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Measured
Period held	1904–2025
Completeness	91.8% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	4 separate periods inside 1904–2025 hold no value. The longest runs from 1930 to 1934 — 5 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1904 and is not continuous from it: 122 years separate the first value from the last, and 92% of the years between them are held. The span is not the record.
Last read from the publisher	2026-10-01
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

How much of the rain came back out

A discharge in cubic metres per second cannot be compared with anything: the larger number may only mean the larger catchment. Divided by the area draining to the gauge it becomes a depth of water over that land, which answers a question a reader already has — of the rain that fell here, how much came back out as river?

Water leaving the catchment above SNAKE RIVER NEAR MORAN, WY, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1904–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Computed by Hydrionis from the published annual mean flow and the catchment area the station's own publisher states. It is not a water balance: the difference between rainfall and runoff is not evaporation alone but also change in groundwater storage, water abstracted and taken elsewhere, and water imported by transfer schemes — which is why a catchment can yield more runoff than the rain that fell on it without anything being measured wrongly. A different area figure rescales every value here by the ratio between them.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	SNAKE RIVER NEAR MORAN, WY (mm)
1904	755
1905	422
1906	501
1907	842
1908	654
1909	907
1910	637
1911	846
1912	768
1913	845
1914	623
1915	443
1916	614
1917	669
1918	841
1919	506
1920	501
1921	616
1922	551
1923	620
1924	467
1925	556
1926	684
1927	598
1928	731
1929	575
1930	556
1931	481
1932	369
1933	624
1934	483
1935	494
1936	481
1937	543
1938	577
1939	576
1940	557
1941	426
1942	472
1943	686
1944	643
1945	374
1946	718
1947	632
1948	743
1949	632
1950	530
1951	697
1952	904
1953	603
1954	650
1955	605
1956	1,034
1957	338
1958	543
1959	526
1960	535
1961	673
1962	397
1963	499
1964	615
1965	729
1966	632
1967	603
1968	571
1969	594
1970	667
1971	869
1972	821
1973	498
1974	878
1975	667
1976	745
1977	464
1978	493
1979	563
1980	542
1981	514
1982	840
1983	742
1984	853
1985	659
1986	928
1987	386
1988	407
1989	329
1990	515
1991	502
1992	724
1993	328
1994	553
1995	556
1996	915
1997	1,118
1998	754
1999	771
2000	519
2001	671
2002	475
2003	603
2004	553
2005	341
2006	474
2007	616
2008	484
2009	666
2010	483
2011	895
2012	608
2013	746
2014	406
2015	477
2016	477
2017	801
2018	727
2019	628
2020	496
2021	693
2022	470
2023	301
2024	445
2025	488

About this series

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Derived Computed by Hydrionis
Period held	1904–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1904 to 2025 is held.
Inputs last read	2026-10-01 · when the records this was computed from were last read from their publishers
Calculation date	2026-08-24 · when the calculation method was last versioned, not a reading of any publisher
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

The snow standing above this water

4 automated snow stations sit inside this drainage area, weighing the snowpack rather than measuring how deep it is.

1,494

Fullest snowpack recorded at Lewis Lake Divide, in 1982 (mm of water)

445

Thinnest, in 1987 (mm of water)

April

Month the pack is usually at its fullest

June

Month the pack has gone by, in half of years

Peak snowpack at Lewis Lake Divide

Water years 1981–2026. Each point is the fullest month of that snow season.

A water year runs October to September and is named for the year it ends, so the snow of one winter stays in one point. The value is the fullest month, not the fullest day: a pack that peaked sharply mid-month reads lower here than a single measurement taken at the right moment would.

View the data behind this chart

Underlying data
Period	Lewis Lake Divide (mm)
1981	473
1982	1,494
1983	957
1984	738
1985	762
1986	1,160
1987	445
1988	699
1989	1,113
1990	685
1991	736
1992	579
1993	818
1994	517
1995	1,052
1996	1,212
1997	1,380
1998	812
1999	1,044
2000	622
2001	460
2002	773
2003	841
2004	752
2005	590
2006	1,113
2007	582
2008	967
2009	851
2010	464
2011	1,312
2012	809
2013	754
2014	1,040
2015	530
2016	672
2017	1,180
2018	1,100
2019	940
2020	717
2021	624
2022	580
2023	978
2024	765
2025	776
2026	715

Read against the river

Lewis Lake Divide and SNAKE RIVER NEAR MORAN, WY both sit in this drainage area, and their records overlap by 44 years. That is the span the two have in common, not a count of years both actually hold — either record may have gaps inside it. The two are shown separately rather than on one axis: millimetres of stored water and cubic metres per second are not commensurable, and a difference between them would mean nothing.

Being in the same drainage area does not put the snowpack upstream of the gauge. A subbasin is an area, and snow on one tributary can join the river below a gauge on another — so a weak relationship here may say more about which tributary was measured than about the snow.

Every gauge Hydrionis holds within this area

Gauges within the Snake Headwaters and what each holds
Gauge	Measures	Values	Record
SNAKE RIVER NEAR MORAN, WY	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	394	1903–2026
Pacific Creek at Moran, WY	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	271	1918–2026
SPREAD CREEK NEAR MORAN, WY	catchment area, annual maximum river flow	2	1918–2026

How these gauges were attached to this water

Assigned by the publisher to a numbered basin Every gauge here is assigned to this drainage area by its own publisher, which issues the area an official code — 17040101. A drainage area is not a river: it contains the tributaries as well as the main channel, and a gauge in it may be on any of them.

What each gauge’s link to this water rests on
Gauge	Evidence	Established
SNAKE RIVER NEAR MORAN, WY	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Pacific Creek at Moran, WY	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
SPREAD CREEK NEAR MORAN, WY	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02

What this record holds

Hydrionis decides which waters get a page, and which of those are offered to search, from what is actually held rather than from how the page reads. Five signals are counted; this record has 4 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	124	yes, 20 or more
Values held	2,764	yes, 1000 or more
Distinct measurements	6	yes, 2 or more
Publishers measuring it	2	yes, 2 or more
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-13011000.json
How to cite this, and who you must credit
How these figures were produced
Request this at a different scale, format or geography

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

Attribution and citation

Suggested citation for Hydrionis

Hydrionis (2026), Snake Headwaters gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-snake-headwaters/

Cite Hydrionis where you rely on values Hydrionis computed, on the method that produced them, or on the compilation itself. The underlying measurements remain the publishers’ and their attribution requirements apply to you directly.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: the Snake Headwaters gauge records changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

None of the contributing licences requires attribution. Crediting the publishers is still good practice and they are listed above.

Where these figures come from

MeasuredHigh confidence2025-06-03

Source: USGS — National Water Information System, USGS site 13011000, annual peak streamflow. Licence: Open.

Method: The instantaneous maximum discharge of each water year as published by USGS, dated to the day it occurred. One value per October-to-September water year; where the publisher lists both a systematic and a historic peak for a year, the larger is the annual maximum. Values the publisher marks as maximum daily averages are not held here, because they are not instantaneous peaks. Values marked as bounded rather than measured are held as censored observations carrying the bound. Cubic feet per second are converted to cubic metres per second and the publisher unit is recorded alongside.

Rating curves are extrapolated at extreme discharges, so the largest values in a peak series carry the largest measurement uncertainty. Data from the U.S. Geological Survey National Water Information System, a work of the United States government and therefore in the public domain.

Retrieved 1 October 2026.