Disaster History · Winter Storm · Case Study
For four days in February, millions of Texans lost power, heat, and running water during the coldest temperatures in a generation. The grid came within minutes of a total collapse that could have taken months to restore.
What happened
Winter Storm Uri swept three successive arctic fronts across Texas between February 10 and 20, 2021. Temperatures dropped below freezing across the entire state. Dallas saw single-digit temperatures. Houston, a subtropical city, stayed below freezing for more than 100 consecutive hours.
Demand for electricity surged as heating systems ran at full capacity. At the same time, power generation collapsed. Natural gas wells froze. Wind turbines iced over. Coal piles froze solid. Power plants across all fuel types failed simultaneously because none were built to operate in sustained sub-freezing conditions.[5]
ERCOT, the grid operator that manages 90% of Texas electricity, ordered rolling blackouts on February 15 to prevent total grid collapse. Those rolling blackouts turned into sustained outages lasting days. The grid came within four minutes and 37 seconds of a complete failure, which would have required a cold-start restoration taking weeks or months.[5]
The average outage lasted 42 hours. Some households went without power for five days. Water systems failed in parallel: 49% of Texans lost running water as pipes froze and water treatment plants lost power.[3]
What failed
Texas operates its own power grid, deliberately isolated from the two national interconnections. This isolation, designed to avoid federal regulation, meant Texas could not import power from neighboring states when its own generation failed.
01
The ERCOT grid is not connected to the Eastern or Western Interconnection. In every other state, when local generation fails, power flows in from neighboring regions. Texas had no such backstop. The 20,000 MW of load shed ERCOT ordered was the largest manually controlled load shedding event in U.S. history.[2]
02
FERC and NERC had recommended winterization after a similar (smaller) Texas freeze in 2011. Those recommendations were voluntary. Most generators did not implement them. The same failure modes that caused outages in 2011 repeated, at larger scale, in 2021.[2]
03
Natural gas is both a fuel for power generation and a heating fuel. When demand spiked, gas pressure dropped. Wellheads froze. Processing plants lost power. The interdependence between gas supply and electricity created a feedback loop: power plants needed gas to run, but gas facilities needed power to operate.[6]
04
Municipal water systems across Texas were not winterized. Pipes burst in homes, businesses, and treatment facilities. Boil-water notices affected 14.6 million people at peak. Some municipalities went weeks without safe water service.[7]
How people died
The Texas Department of State Health Services attributed 210 deaths directly to the storm, most from hypothermia and carbon monoxide poisoning.[8] Independent analyses using excess mortality data estimate the true toll between 426 and 978, with a midpoint estimate of approximately 700.[1]
Carbon monoxide deaths followed a grim pattern: families running car engines in closed garages, bringing charcoal grills indoors, or operating portable generators too close to the house. These deaths were concentrated in communities that had never experienced sustained freezing and did not own cold-weather survival equipment.
Hypothermia deaths skewed heavily toward elderly residents and people dependent on powered medical equipment. CPAP machines, oxygen concentrators, and home dialysis systems all require electricity. When power failed, the backup plan for many households was simply to wait.
The lesson is the same as Maria, applied to a different climate: the grid is a single point of failure for everything. Households with an indoor-rated propane heater, a CO detector, and even a basic understanding of single-room heating strategy had dramatically different outcomes than those without.
What changed
FERC and NERC issued mandatory reliability standards in February 2023 requiring power generators and transmission operators to implement cold weather preparedness plans and protect critical equipment against extreme cold. Compliance is enforceable with fines.[9]
Passed in June 2021, these bills required weatherization of power generation and natural gas infrastructure, reformed ERCOT governance, and created a statewide electricity supply chain mapping system.[10]
The gap between the official count of 246 and independent estimates of 700+ echoed the same counting failures seen in Puerto Rico after Maria. Researchers noted that only 77 of Texas's 254 counties reported any storm-related deaths, suggesting systematic underreporting.[1]
Uri reignited the debate over connecting ERCOT to the national grid. As of 2026, Texas remains isolated. The tradeoff between regulatory independence and resilience remains unresolved.
Where this connects
Tier 02 · Sustain
Single-room heating, backup power tiers, no-power cooking, and the sanitation plan that Uri proved essential.
Build your buffer
Hazard Guide
Pipe protection, CO safety, heat strategy, and the supply checklist for sustained cold-weather outages.
See the guide
Self-Reliance · Energy
Power banks, portable power stations, generators, and solar. Three honest tiers, three honest price tags.
Compare options
Sources
Last reviewed: May 2026 · NWS Editorial Team