Category 3 winter storm and ice storm in the United States
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The February 13–17, 2021 North American winter storm was a crippling winter and ice storm that had widespread impacts across the United States, Northern Mexico, and parts of Canada from February 13 to 17, 2021. The storm, unofficially referred to as "Winter Storm Uri" by the Weather Channel, started out in the Pacific Northwest and quickly moved into the Southern United States, before moving on to the Midwestern and Northeastern United States a couple of days later.
The storm resulted in the National Weather Service issuing various winter weather alerts impacting over 170 million Americans. Over 9.9 million people in the U.S. and Mexico experienced blackouts, many due to a major power crisis in Texas, which became the largest in the U.S. since the Northeast blackout of 2003. The storm contributed to a severe cold wave that affected most of North America. The storm also brought severe destructive weather to Southeastern United States, including several tornadoes. On February 16, there were at least 20 direct fatalities and 13 indirect fatalities attributed to the storm; by January 2, 2022, the death toll had risen to at least 290, including 276 people in the United States and 14 people in Mexico. 
The National Oceanic and Atmospheric Administration officially documented US$26.5 billion in damage in the United States from the winter storm. Aon PLC, a finance company, estimated the system to have cost over $196.5 billion in damages, including at least $195 billion in the United States and over $1.5 billion in Mexico. This would make it the costliest winter storm on record and the costliest natural disaster recorded in the United States at the time. It was also the deadliest winter storm in North America since the 1993 Storm of the Century, which killed 318 people.
Meteorological history.
On February 13, a frontal storm developed off the coast of the Pacific Northwest and moved ashore, before moving southeastward, with the storm becoming disorganized in the process. During this time, the storm reached a minimum pressure of over the Rocky Mountains. On the same day, The Weather Channel gave the storm the unofficial name "Winter Storm Uri"; the Federal Communications Commission adopted the name in their reports from February 17. From February 12 to 13, a trough dipped southward from Northern California into northern Mexico, which channeled moisture from Texas towards the storm, as the system moved southeastward. Over the next couple of days, the storm began to develop as it entered the Southern United States and moved into Texas. From February 13 to 14, a second, much larger trough developed over Central United States, aided by a southward shift from the polar vortex, while the winter storm moved into Texas. The trough became fully developed by February 15, channeling significant amounts of moisture into the winter storm and also contributing to a historic cold wave that affected most of the Central and Eastern United States. Winds in the jet stream reached 170 mph (275 km/h) around the trough. On February 15, the system developed a new surface low off the coast of the Florida Panhandle, as the storm turned northeastward and expanded in size.
On February 16, the storm developed another low-pressure center to the north as the system grew more organized, while moving towards the northeast. Later that day, the storm broke in half, with the newer storm moving northward into Quebec, while the original system moved off the East Coast of the U.S. By the time the winter storm exited the U.S. late on February 16, the combined snowfall from the multiple winter storms within the past month had left nearly 75% of the contiguous United States covered by snow, which was the largest amount of snow cover seen in the United States since early 2003. On February 17, the storm's secondary low dissipated as the system approached landfall on Newfoundland, intensifying in the process. At 12:00 UTC that day, the storm's central pressure reached , as the center of the storm moved over Newfoundland. On the same day, the storm was given the name "Belrem" by the Free University of Berlin. The storm continued to strengthen as it moved across the North Atlantic, with the storm's central pressure dropping to by February 19. On February 20, the storm developed a second-low pressure area and gradually began to weaken, as it moved northwestward towards Iceland. Afterward, the storm turned westward and moved across southern Greenland on February 22, weakening even further as it did so. The storm then stalled south of Greenland, while continuing to weaken, before dissipating on February 24.
Preparations and impact.
United States.
On February 14, the expected impacts from the storm resulted in over 170 million Americans being placed under various winter weather alerts across the United States, which saw the largest portion of the country covered by winter weather alerts in 15 years. Over 120 million of those people were placed under winter storm warnings or ice storm warnings by the National Weather Service. The winter storm caused power grids to fail across the U.S., causing blackouts for over 5.2 million homes and businesses, the vast majority of which were in the state of Texas, which became one of the largest blackout events in modern U.S. history, the largest one since the Northeast blackout of 2003. The storm was initially reported to have caused 70 deaths across the United States, later updated to at least 276 people dead, 246 of them in Texas. A BuzzFeed study in May 2021 estimated that the winter storm may have killed a total of 702 people in Texas, which would add hundreds of deaths to the official death toll if verified. The system was estimated by NOAA to have cost $21 billion in damage in the United States, making it the costliest winter storm in U.S. history at the time. City of Austin and Travis County officials estimated that the winter storm caused at least $195 billion in damage in Texas, making the winter storm the single-costliest natural disaster in the history of Texas and the United States as a whole. Some insurance firms had estimated a damage total of between 195 and 295 billion dollars.
Northwest.
The winter storm was the second of the two snowstorms that swept through the region within a one-week period. of snow in Seattle, Washington, compounded the previous storm. This was the largest two-day snowfall recorded in Seattle since 1972.
The Portland metro area was hit very hard by the storm, which brought a mix of snow and ice to the region. of snow fell at Portland International Airport on February 12–13, the most snow to fall over this city in a two-day period since 1968. Over 270,000 people were left without power in the region, with of power lines needing to be restored. The storm led to the largest power outage in state history. Around of Interstate 84 was shut down due to the storm. Governor Kate Brown declared a state of emergency. Four people were killed in Oregon by carbon monoxide poisoning. Damage in Oregon totaled $26,874,426.
 of snow fell in Boise, Idaho, during this same time period, making this the largest recorded two-day snowfall event for that city since 1996. In Salt Lake City, the made this storm their snowiest February day on record.
Southwest.
The storm brought heavy snow and bitterly cold temperatures to Colorado and New Mexico. Snow amounts in Colorado ranged from a few inches in the north to over in the San Juan Mountains in northern New Mexico and southern Colorado. In New Mexico, the storm system brought a combination of heavy snow, strong winds, and bitterly cold temperatures. On February 14, a Blizzard Warning was issued for the Albuquerque metro area due to strong winds exceeding , cold temperatures, and blowing snow. Meanwhile, Winter Storm Warnings were issued for much of the rest of New Mexico. Up to of snow fell in the mountains of northern and central New Mexico. Snow amounts in the Albuquerque metro area ranged from . Interstate Highway 40 through the Albuquerque metro area was closed for several hours due to numerous motor vehicle crashes caused by the icy conditions. Southern New Mexico received up to of snow accumulation, with locally higher amounts in the mountains.
Central and Southern Plains.
With the threat of icing, the Texas Department of Transportation (TxDOT) pre-treated roadways, using a brine-salt mix, across six Southeast Texas counties. For the first time on record, the National Weather Service (through its 13 regional offices serving Texas and adjoining portions of Oklahoma, New Mexico, Arkansas and Louisiana) issued Winter Storm Warnings for all 254 counties in the state. In addition, Houston saw their first ever wind chill warning, as wind chills dipped to . Wind chills predicted to be at or below promoted the first ever wind chill warning for Dallas as well.
On February 14–15, the storm dropped prolific amounts of snow across Texas and Oklahoma. As a result of the winter storm and a concurrent cold wave, power grids—unable to sustain the higher-than-normal energy and heating demand from residential and business customers—failed across the Texas Interconnection; at the peak of the outages, at least 4.5 million Texas residents were left without electricity. Two of the electricity reliability commissions servicing the Southern U.S., the Southwest Power Pool (SPP) and the Electric Reliability Council of Texas (ERCOT), ordered rolling blackouts for 14 states amid the frigid temperatures, in an attempt to manage the strain on the power grid and prevent widespread, long-duration blackouts. The controlled outages were initiated after the Southwest Power Pool declared Level 3 Emergency Energy Alerts on both February 15 and 16; the SPP and ERCOT faced criticism by government officials and residents in the region for the limited advanced notice of the outages, and for not outlining the specific areas serviced by SPP partner utilities that would be affected.
At one point during the rolling outages, over 4.2 million people across the south-central states were left without power, with over 3.5 million of them in Texas alone. The rolling blackouts led to calls by Governor Greg Abbott for the Texas Legislature to conduct investigations into preparations and decisions undertaken by ERCOT in advance of the storm. Some of the blackouts were initiated as several cities throughout the Central and Southern Plains experienced record overnight low temperatures: on February 16 alone, daily record lows were broken in Oklahoma City (, the city's coldest temperature since 1899 and its second-coldest on record), Dallas (, the city's coldest temperature since 1930 and its second-coldest on record), Houston (, the city's coldest temperature since 1989), San Antonio (, the city's coldest temperature since 1989) and Little Rock (, the city's coldest temperature since 1989), with all-time low temperatures being set in Fayetteville, Arkansas () and Hastings, Nebraska ().
Rolling blackouts, longer-duration power outages and ice accretion caused by the precipitation and unusually cold temperatures (for the region's climate) caused widespread disruptions to water distribution systems across the Southern Plains. There were water line breaks in many areas, and power disruptions affected water treatment plants in parts of the region that forced several cities—including Houston, San Antonio, Fort Worth, Abilene, Austin, Killeen and Arlington, Texas; and Shreveport, Louisiana—to enact residential boil-water orders (i.e., to boil drinking water to kill pathogens); By February 18, more than 13 million people in Texas lived in areas where boiling water was advised, or using bottled water if heating was not possible. This led to shortages of bottled water in Houston grocery stores. Pipe bursts caused significant damage to numerous residences in the Dallas area and other areas of North Texas.
After consulting Dallas Mayor Eric Johnson, two National Hockey League games between the Nashville Predators and the Dallas Stars that were scheduled for the evenings of February 15 and 16 at American Airlines Center were postponed. In contrast, the Oklahoma City Thunder opted to hold their February 16 home game against the Portland Trail Blazers as scheduled, even as most other buildings in Downtown Oklahoma City decided to turn off lighting and electrical equipment overnight to reduce strain on the city's power grid; the NBA team stated that Chesapeake Energy Arena would take steps to conserve power while the game was being played, including turning off concourse lighting, video panels, exterior signage and most outdoor lighting. The Memphis Grizzlies also