In this morning’s “Today in Energy” (https://www.eia.gov/todayinenergy/detail.php?id=46896), US EIA explains what happened with the freeze hit:
During the cold snap that affected much of the central part of the country, U.S. dry natural gas production fell to as low as 69.7 billion cubic feet per day (Bcf/d) on February 17, a decline of 21%, or down nearly 18.9 Bcf/d from the week ending February 13. Natural gas production in Texas fell almost 45% from 21.3 Bcf/d during the week ending February 13 to a daily low of 11.8 Bcf/d on Wednesday, February 17, according to estimates from IHS Markit. Temperatures in Texas averaged nearly 30 degrees Fahrenheit lower than normal during the week of February 14.
The decline in natural gas production was mostly a result of freeze-offs, which occur when water and other liquids in the raw natural gas stream freeze at the wellhead or in natural gas gathering lines near production activities. Unlike the relatively winterized natural gas production infrastructure in northern areas of the country, natural gas production infrastructure, such as wellheads, gathering lines, and processing facilities, in Texas are more susceptible to the effects of extremely cold weather. [Emphasis added]
After reaching a daily low on February 17, natural gas production in Texas began increasing as temperatures started to rise. Daily production reached an estimated 20.9 Bcf/d on February 24, only about 0.3 Bcf/d lower than the average in the week ending February 13.
That explains the evaporation of dispatched power.
What about the nondispatched? The wind turbines?
Well, Max Rust and Kyle Kim already addressed that in the piece in the aftermath of the freeze: https://www.wsj.com/articles/why-cold-weather-cut-the-power-in-texas-11613765319
Following a similar weather event in 2011, plant operators in Texas created a set of best practices for winterizing equipment, but these were voluntary recommendations, according to Dan Woodfin, senior director of system operations at Ercot.
Another major source of Texas’ electricity also susceptible to the cold contributed in part to the outages. Wind turbines installed in warm weather climates can generally operate above -4 degrees Fahrenheit but will shut down in colder temperatures. Ice buildup on the blades can also lead to slower rotations and even shut down a turbine. In northern climates such as Canada and Scandinavia, winterization measures are typically built into the turbines during manufacturing, but can be retrofitted to turbines already in operation.
Econophysics2020 
