Public Information Statement
Statement as of 9:30 am CST on December 5, 2013
-family of services
-NOAA weather wire service
-emergency managers weather information network
other NWS partners... users... and employees
From: Dan Reilly
acting meteorologist in charge
weather forecast office Houston/Galveston
Subject: changes in gage reporting and flood categories for stream
gage near Moss Bluff, Texas on the Trinity River / mbft2/
The USGS has changed the gage datum fir the stream gage near Moss
Bluff, Texas on the Trinity River from 0.0 feet above National
geodetic vertical datum of 1929 /ngvd29/ to 0.0 feet above North
American vertical datum of 1988 /navd88/.
Because of this change effective at 0800 on March 1 2014... every
stage observation will be 2.84 feet lower that it would have been
under the old ngvd29 system. To ensure consistency in NWS forecast
and warning services... this change also requires adjustment to flood
category elevations. The new flood category stages will be as
1. New minor flood stage is 12.2 feet above navd88. The previous
flood stage was 15.0 feet above ngvd29.
2. The new moderate flood stage is 15.2 feet above navd88. The old
moderate flood stage was 18.0 feet above ngvd29.
3. The new major flood stage is 17.2 feet above navd88. The old
major flood stage was 20 feet above ngvd29.
The National Weather Service welcomes public feedback. If you have
any questions or comments on this change... please contact:
senior service hydrologist
Houston/Galveston National Weather Service forecast office
1353 FM 646 W, ste 202
Dickinson, Texas 77539
Phone: 281-337-5074 ext 228