Texas 2021: What Actually Failed, in Order

Winter Storm Uri is the best-documented modern grid failure in the United States, and it is far more useful for planning than any hypothetical. It happened, it was investigated, the failure sequence is on record, and the cascade it produced is the one most households would actually face.

Mid-February 2021. Roughly 4.5 million Texas homes and businesses lost power, many for multiple days, in temperatures well below freezing. The official state death toll was 246; independent analyses put the figure considerably higher.

ERCOT's own account is that the grid came within minutes of uncontrolled collapse — a failure that would have taken weeks to months to restore rather than days.

The failure sequence

The popular version blames wind turbines. The investigations found something considerably more instructive.

Demand rose beyond any winter forecast. Texas heats predominantly with electricity, so a deep freeze drives load in the same direction as a heatwave — up, sharply, and simultaneously across the entire state.

Natural gas production froze at the wellhead. This was the single largest contributor. Gas wells produce water alongside gas, and unprotected wellheads, gathering lines, and processing equipment freeze. Production dropped sharply, statewide, over the course of the event.

Gas plants couldn't get fuel. The generators were operational. The fuel wasn't arriving. Some plants that could have run had no gas to burn, and gas compressor stations themselves lost electrical power, which further reduced deliverability — a feedback loop where the power failure worsened the fuel failure.

Instrumentation froze. Sensing lines, transmitters, and control equipment at plants of every fuel type iced up. This included a nuclear unit, which tripped offline because a frozen sensing line told it something was wrong. The reactor was fine. A pressure sensor wasn't.

Wind output fell, but it was the smaller share. Turbines iced and output dropped, contributing meaningfully but well below the gas system's contribution. Wind was also forecast to produce relatively little during the period, so much of the shortfall was already planned around.

Rolling outages became sustained outages. With that much capacity gone, load shedding could not be rotated the way it's designed to be. Circuits that were supposed to be off for forty-five minutes stayed off for days.

The part that matters most for households

Losing power was not the worst of it. The cascade was.

Water failed next. Municipal water systems need electricity to run pumps and maintain pressure. As pressure dropped, pipes froze and burst, and systems that lost pressure entirely had to issue boil-water notices — which is a bitter instruction to a household with no power to boil anything. Millions of people were under those notices, in some cases after power had already returned.

Heat failed even where gas kept flowing. This is the detail most people get wrong. A modern gas furnace requires electricity for its blower motor, ignition, and control board. Gas in the line is not heat if the furnace can't run. Households with functioning gas service sat in cold homes because the furnace needed a hundred watts it didn't have.

Then plumbing failed. Unheated houses drop below freezing, pipes burst, and the damage arrives after the outage ends. A significant share of the total economic loss from Uri was burst-pipe damage rather than the outage itself.

That's the sequence to plan against: power out, water out, heat out, then structural damage. Each stage was caused by the previous one.

Why Texas specifically

Two structural facts made Texas more exposed than most of the country.

ERCOT is largely islanded. The continental US has three interconnections — Eastern, Western, and Texas. The first two trade power across enormous areas, so a region in trouble can import from neighbours. ERCOT's limited ties to the other two meant Texas could not import its way out at anything like the needed scale.

Winterisation was not mandated. After a similar 2011 event, federal regulators recommended winterising generation and gas infrastructure. Those recommendations were largely voluntary. A decade later the same equipment froze for the same reasons.

Neither fact was secret. Both had been documented after the previous event.

What generalises to everywhere else

Don't read this as a Texas story. Three findings apply anywhere.

Fuel supply is a failure mode, not just generation. A grid can have adequate generating capacity and still fail because the fuel doesn't reach it. Reserve margin numbers count plants, not fuel deliverability.

Correlated failure defeats reserve margins. Planning buffers assume generators fail independently. Extreme weather makes them fail together, for the same reason, at the same time as demand peaks. This is the central lesson and it applies to every region.

Interdependency is the real risk. Power, water, gas delivery, and heat are not four separate systems. They are one system with four names, and the failure of any one degrades the others. Preparing for "an outage" while assuming water and heat continue is preparing for something that doesn't happen.

What a household plan looks like against this

Heat that doesn't need the grid. The single highest-value item on this list. A furnace that won't run without electricity is the most common preventable failure. Options are a generator or battery sized to the blower, a properly vented indoor-safe heater with fuel stored, or a wood stove. The blower draw is usually a few hundred watts — modest, and the sizing calculator will tell you exactly what you need.

Water stored before the event. Not filtration — storage. A filter needs a source, and the source is what failed. A bathtub filled when the forecast turns handles sanitation; potable water needs proper containers, and the water storage planner covers the arithmetic.

Knowing how to shut off and drain your water main. Burst pipes caused enormous damage that was largely preventable. If the house is going to drop below freezing and you can't heat it, drain the system.

Food that needs no cooking and no refrigeration. With power and gas both compromised, anything requiring either is theoretical.

A way to charge a phone for several days, because the outage lasted days rather than hours and information mattered.

The single sentence version

The grid failed because the fuel system froze, and everything downstream of the grid — water, heat, and eventually the plumbing in people's walls — failed with it.

Plan for the cascade, not the outage.

Related: How to read a grid reliability report for your region explains the reserve margin numbers and why correlated failure defeats them.

Last reviewed: July 2026