Rivers in Texas

Blanco River at San Marcos

Hays County, TexasNWS BSMT2USGS 08171350New Braunfels office

Below flood stage
6.31ftStage

Observed Sun, Sep 20, 11:45 AM CDT

Flood stage
18.00 ft
Record crest
43.10 ft2015

Open the live map with the river flood outlook

Flood stages and impacts

CategoryStage
Major flood30.00 ft
Moderate flood24.00 ft
Minor flood18.00 ft
Action13.00 ft
  1. 43.00 ftWater is several inches deep in the Walmart and CVS parking lots and other business in the region. Water surrounds the Balnco River Lodge apartments. Water into many homes and businesses along the river between I-35, SH 80 and River road. Water over teh Hwy 80 bridge at San Marcos
  2. 30.00 ftWater begins to enter many homes and businesses begin to have water entering the structures. More secondary and even primary raods become impassable for vehicles
  3. 24.00 ftLowest homes are threatened. Water beings to cut off secondary roads near the river
  4. 18.00 ftRoadways and low bridges along the river are flooded. Vehicles cannot pass. Livestock can be stranded.
  5. 13.00 ftOverbank conditions may cut off livestock and low bridges near the river

Flood outlook

Chance of flooding, September to November

CategoryChance
Minor flooding21%
Moderate flooding11%
Major flooding8%

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued August 28, 2026.

Crest history

8 crests on NOAA’s list since 2015.

#DateStage
1May 24, 201543.10 ft
2October 30, 201542.56 ft
3October 14, 202124.71 ft
4May 9, 201924.14 ft
5May 4, 201920.53 ft
6September 26, 201615.23 ft
7April 11, 201713.49 ft
8August 27, 201710.93 ft

Most recent crests

  • October 14, 2021: 24.71 ft
  • May 9, 2019: 24.14 ft
  • May 4, 2019: 20.53 ft
  • August 27, 2017: 10.93 ft
  • April 11, 2017: 13.49 ft
  • September 26, 2016: 15.23 ft
  • October 30, 2015: 42.56 ft
  • May 24, 2015: 43.10 ft

Nearby

Upstream, downstream and the gauges around this one.

What this means

Forecasts by the West Gulf River Forecast Center. Forecasts are issued routinely year-round. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 24 hours into the future from the forecast issuance time.

Sources

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.