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Llano River near Mason

Highest listed crest 37.00 ftFlood stage 18.0 ft22 crests since 1969

The Llano River near Mason crested at major flood stage 5 times among the 22 crests the National Weather Service lists from 1969 to 2026. The highest, 37.00 ft on September 8, 1980, was major flooding, 19.00 feet above flood stage.

The gauge

Highest listed crest
37.00 ft
September 8, 1980; 260,000 cubic feet per second
Flood stage
18.0 ft
Major flooding from 28.0 ft
Crests at major
5
132nd of 370 gauges in Texas
Most recent flood crest
July 18, 2026
26.97 ft, moderate flooding
Location
Mason County
Texas

Flood stages

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

Flood categories, Llano River near Mason
Action stage11.05Nov 15, 2001The level at which the NWS or its partners begin to take action
Flood stage (minor)18.06Jul 14, 2025Minimal or no property damage, but possibly some public threat
Moderate flood stage24.05Jul 18, 2026Some inundation of structures and roads near the stream
Major flood stage28.05Jul 4, 2025Extensive inundation of structures and roads

Every listed crest

22 crests from 1969 to 2026. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Llano River near Mason, 1969 to 2026 10203040ft Flood stage 18.0 ftMajor 28.0 ft Oct 5, 1969: 18.53 ft, minor flooding; 55,700 cubic feet per secondOct 13, 1973: 26.30 ft, moderate flooding; 151,000 cubic feet per secondApr 16, 1977: 16.64 ft, action stage; 52,000 cubic feet per secondAug 3, 1978: 21.35 ft, minor flooding; 92,500 cubic feet per secondSep 8, 1980: 37.00 ft, major flooding; 260,000 cubic feet per secondOct 13, 1981: 25.06 ft, moderate flooding; 114,000 cubic feet per secondDec 31, 1984: 25.22 ft, moderate flooding; 115,000 cubic feet per secondJul 12, 1988: 18.40 ft, minor flooding; 61,600 cubic feet per secondMay 3, 1990: 17.49 ft, action stage; 55,200 cubic feet per secondSep 18, 1990: 14.78 ft, action stage; 38,000 cubic feet per secondSep 17, 1991: 10.13 ft, below flood stage; 16,400 cubic feet per secondAug 24, 1998: 16.38 ft, action stage; 49,300 cubic feet per secondNov 4, 2000: 32.00 ft, major flooding; 170,000 cubic feet per secondNov 15, 2001: 17.74 ft, action stage; 60,100 cubic feet per secondNov 17, 2004: 21.59 ft, minor flooding; 92,817 cubic feet per secondJun 13, 2008: 31.33 ft, major flooding; 163,984 cubic feet per secondOct 8, 2018: 22.68 ft, minor flooding; 101,000 cubic feet per secondOct 16, 2018: 34.21 ft, major flooding; 193,000 cubic feet per secondJul 24, 2024: 24.08 ft, moderate flooding; 78,701 cubic feet per secondJul 4, 2025: 29.91 ft, major flooding; 125,843 cubic feet per secondJul 14, 2025: 20.29 ft, minor flooding; 47,895 cubic feet per secondJul 18, 2026: 26.97 ft, moderate flooding; 108,033 cubic feet per second Highest, 37.00 ft, Sep 8, 1980 197019801990200020102020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Llano River near Mason 1960s: 1 1970s: 2 1980s: 4 4 1990s: 0 2000s: 3 2010s: 2 2020s: 4 1960s1970s1980s1990s2000s2010s2020s
  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.
  3. 1 crest measured on an earlier gauge datum is left out: 46.00 ft on Jun 14, 1935.

Highest crests

Highest listed crests, Llano River near Mason
1Sep 8, 198037.00+19.00Major260,000
2Oct 16, 201834.21+16.21Major193,000
3Nov 4, 200032.00+14.00Major170,000
4Jun 13, 200831.33+13.33Major163,984
5Jul 4, 202529.91+11.91Major125,843
6Jul 18, 202626.97+8.97Moderate108,033
7Oct 13, 197326.30+8.30Moderate151,000
8Dec 31, 198425.22+7.22Moderate115,000
9Oct 13, 198125.06+7.06Moderate114,000
10Jul 24, 202424.08+6.08Moderate78,701
11Oct 8, 201822.68+4.68Minor101,000
12Nov 17, 200421.59+3.59Minor92,817
13Aug 3, 197821.35+3.35Minor92,500
14Jul 14, 202520.29+2.29Minor47,895
15Oct 5, 196918.53+0.53Minor55,700
16Jul 12, 198818.40+0.40Minor61,600
17Nov 15, 200117.74−0.26Action60,100
18May 3, 199017.49−0.51Action55,200
19Apr 16, 197716.64−1.36Action52,000
20Aug 24, 199816.38−1.62Action49,300
21Sep 18, 199014.78−3.22Action38,000
22Sep 17, 199110.13−7.87Below flood stage16,400

The worst floods along the Llano River

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

October 16, 2018: 34.21 ft here, major flooding

  • LlanoTX · Oct 16, 2018 · 40.14 ft · Major
  • JunctionTX · Oct 16, 2018 · 28.39 ft · Moderate

November 4, 2000: 32.00 ft here, major flooding

  • JunctionTX · Nov 3, 2000 · 35.08 ft · Major · its highest
  • LlanoTX · Nov 4, 2000 · 28.65 ft · Major

July 4, 2025: 29.91 ft here, major flooding

  • LlanoTX · Jul 4, 2025 · 27.07 ft · Major

Gauges on the Llano River

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

Flood gauges on the Llano River
JunctionTX16.035.08 ft, Nov 3, 20003
Mason this gaugeTX18.037.00 ft, Sep 8, 19805
LlanoTX10.041.50 ft, Jun 14, 19356

Other gauges in Mason County

Flood gauges in Mason County
Mason17.024.00 ft, Aug 3, 19780

Mason County: every hazard · River floods across the country · Texas

NOAA National Water Prediction Service, gauge MLRT2, 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.