Major Flooding In Texas Halloween Morning

Doppler Radar Estimate of rainfall from October 30 and October 31 shows up to 14 inches of rainfall near Austin, Texas.
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A typical early fall, flood event occurred from the evening of October 30 through late afternoon on October 31, 2013. There was widespread rainfall of 2-4 inches across portions of eight counties; substantial areas of 6-10 inches across Hays, western Comal, and central Travis counties; and a bull’s -eye of 12-14 inches in a narrow swath from Wimberley to Driftwood. The rainfall resulted in major flash flooding along the I -35 Corridor from Georgetown to New Braunfels, and major to record flooding for a number of creeks and rivers. The primary ingredients producing the event included an upperlevel
trough that moved from northern New Mexico across the Texas Panhandle and into Kansas and Oklahoma. Meanwhile, a w
eak surface trough stalled along Interstate 35, which provided the
concentrating focus for moist Gulf air (dewpoints from 65-70 °F
). The general lifting of air from the approaching trough,
increasing instability with cool, dry air aloft, over warm, moist air near the ground, and convergence along the surface trough produced
showers and thunderstorms. In addition to the severe storms, the amount of water vapor (i.e., precipitable water) measured
by weather balloon at Corpus Christi Tuesday evening was
2.08 inches, which is about two standard deviations above the mean value for late October.
The average wind moved storms along quickly,
but redevelopment along the surface trough led to multiple storms passing over the same locations

called echo training. Both the high moistu
re content and echo training strongly
indicated the potential for heavy rain and flash flooding
. Resulting rainfall amounts were heavy along and
just west of I-35, including peak amounts of
14 inches between Wimberley and Driftwood.

Graph shows the rapid rise of Onion Creek as the massive rainfall created a major flooding situation in Texas.