Introduction

On May 23, 2015, a flash flood formed in the Blanco River and slammed the residents of Wimberley, TX. Houses were instantaneously removed from their foundations, giant trees were snapped in half, and tree bark was removed for over 30 feet into the air because the depth of the flood was so great. The volume and power of this flood was unprecedented in recorded history.

This flood crested at 43 feet, or 30 vertical feet above its normal flood stage of 13 feet. The peak discharge is unknown but exceeded 70,000 cubic feet per second.  At least 11 people perished in the flood. Now two weeks later, some bodies have yet to be recovered.

Wimberley, Texas

Wimberley, Texas is a very nice town located between Austin and San Antonio (Figure 1). When arriving in Wimberley, you are greeted with a sign that says: “A little bit of heaven, welcome to Wimberley” (Figure 2). On the day of the flood, Wimberley was more like hell than heaven.

Figure 1 – Wimberley is about 1 hour southeast of Austin, shown in the small polygon area.

Figure 2 – The Wimberley greeting sign.

Just past this sign is the Blanco River. The Blanco River flows through the town (Figure 3).  Many residents lived along the river shoreline and many homes were located above the 500-year floodplain, above the shear rock cliffs that line the river. Based on Google Earth pictures, this river can appear to be dry at times throughout the year, with only pools of water visible in certain sections.

Figure 3 – Picture of the Blanco River before the May 23rd, 2015 flash flood decimated the area.

Figures 4 and 5 show the Blanco river two weeks after the flood. You can click on these high-resolution images to see a lot of detail.

Figure 4 – The Blanco river, viewed upstream. This picture was taken just past the welcome sign shown in Figure 2 and just in the upper right-hand corner of Figure 3.

Figure 5 – The Blanco river downstream of the bridge.

The Flood Aftermath

Two weeks after the flood, my wife, my son and I decided to visit Wimberley to see what the flood did to the community. What we saw is shown below in a series of high-resolution picture collages. Figures 6 through 12 are images taken along the river in the Wimberley community. You can click on any of the collages to see the full details.

The devastation was overwhelming. Our day trip was emotionally taxing. This clean-up is going to take a long time and I suspect the flood zones will be remapped.

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Upcoming Articles

To understand how this could happen, I am going to a little hydrology research. I’m planning on using Alteryx and Tableau to visualize this event. I’ll be getting back to the climate database I have previously written about to understand how severe rainfall could lead to such a catastrophic flash flood.

At this time, I have no idea how this research will end, but it should be interesting. I guess you can take the boy out of geology, but you can’t take geology out of the boy. Stay tuned…