The winter storm was the second of the two snowstorms that swept through the region within a one-week period. 11.1 inches (28 cm) 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. 9.4 inches (24 cm) 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, and the Governor declared a state of emergency.
9.9 inches (25 cm) of snow also fell in Boise, Idaho during this same time period, making this the largest recorded two-day snowfall for that city since 1996.
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 2 feet (0.61 m) in the San Juan Mountains in the southern part of the state. In New Mexico, the storm system brought a combination of heavy snow, strong winds, and bitterly cold temperatures. On February 14th, a Blizzard Warning was issued for the Albuquerque metro area due to strong winds exceeding 50 mph, cold temperatures, and blowing snow. Meanwhile Winter Storm Warnings were issued for much of the rest of New Mexico. Up to two feet of snow fell in the mountains of northern and central New Mexico. Snow amounts in the Albuquerque metro area ranged from 2 to 6 inches. Interstate 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 two inches of snow accumulation, with locally higher amounts in the mountains.
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.
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 (−14 °F [−26 °C], the city's coldest temperature since 1899 and its second-coldest on record), Dallas (−2 °F [−19 °C], the city's coldest temperature since 1930 and its second-coldest on record), Houston (13 °F [−11 °C], the city's coldest temperature since 1989), San Antonio (12 °F [−11 °C], the city's coldest temperature since 1989) and Little Rock (−1 °F [−18 °C], the city's coldest temperature since 1989), with all-time low temperatures being set in Fayetteville, Arkansas (−20 °F [−29 °C]) and Hastings, Nebraska (−30 °F [−34 °C]). Wind chills on the morning of February 15th were in the minus 50s as far South as the Kansas/Nebraska border.
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. Water line breaks occurred in many areas, and power disruptions impacted 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 for one minute in order kill bacteria and other pathogens); By February 18, more than 13 million people in Texas lived in areas covered by boil-water advisories. In cases where residents had no energy sources to heat water, purchasing bottled water was advised; in Houston, this led to shortages of bottled water in grocery stores. In addition, 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 NHL 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, and two games between the Stars and the Tampa Bay Lightning scheduled for February 18 and 20 were also 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.
Due to the deregulated electricity market and the spike in demand, since February 10, wholesale electricity prices have gone up in some places by 10,000 percent. As a result, some Texans are receiving exceptionally expensive electric bills as high as $450 for one day of use. On February 18, San Antonio firefighters fighting a large apartment fire caused by a water heater explosion were forced to use water trucks as fire hydrants had become inoperable due to water shortages. On February 17, U.S. Senator Ted Cruz (R-TX) stirred controversy when he was filmed boarding an airplane to Cancún, Mexico with his family. He returned to Houston the following day, and admitted he had scheduled the vacation to avoid freezing conditions inside their home.
In Oklahoma, winter storm warnings were issued for all 77 counties in the state ahead of the storm by National Weather Service offices in Norman, Tulsa, Amarillo and Shreveport. Governor Kevin Stitt also issued a statewide winter weather State of Emergency on February 12, as the state was already dealing with effects from minor winter weather events and prolonged sub-freezing temperatures from the days prior. Widespread areas of 3–8 inches (7.6–20.3 cm) were recorded throughout the state with locally higher amounts in some areas. Roosevelt saw 12 inches (30 cm) of snow, the highest total measured in the state during the event.
The heavy, blowing snow caused massive travel issues across the state on February 14. By 5:20 p.m. CST that day, the Oklahoma Highway Patrol had responded to 56 non-injury collisions, 24 injury collisions, and 116 motorist assists. A fiery crash involving multiple vehicles, including two semi-trucks, shut down the Turner Turnpike near Hiwassee Road in northeastern Oklahoma County, with westbound traffic being diverted to the Kickapoo Turnpike and eastbound traffic being diverted to I-35. Another vehicle collision on I-35 near Braman caused one fatality. The record cold temperatures during the event also caused a dam at Lake Overholser to completely freeze over. On February 18, the Oklahoma Department of Environmental Quality issued boil-water recommendations for residents who experienced water service outages from the bitter temperatures and snowpack; Oklahoma City, Tulsa and other cities (including Shawnee, Blackwell and Spencer) and rural water districts in the state issued temporary residential boil-water advisories or mandatory boil orders between February 18 and February 20.
By February 16, the storm had killed at least 17 people across the South. By February 18, the death toll rose to at least 47. At least 10 people in Texas died in weather-related incidents since February 14, including a mother and a child due to carbon monoxide poisoning. Eight other people in the South, outside of Texas, have died as a result of the system or through indirect storm-related incidents. In Kentucky, a man died after slipping on ice and then succumbing to hypothermia.
Chicago along with other cities in northern Illinois received up to 14–17 in (36–43 cm) of snow along with winds up to 20 mph (32 km/h). Indianapolis, Indiana received about 7 inches of snow as well as Detroit, Michigan also had 7 inches of snow. Toledo, Ohio received 14.5 in (37 cm) of snow, the third-highest two-day snowfall record, and the highest since 1912. Other Northern Ohio cities received up to 10–12 in (25–30 cm) of snow while cities in the central part received up to 3 in (7.6 cm) of snow like in Columbus, Ohio.
Virginia implemented a winter weather state of emergency effective February 12, which continued into the following week's storm.
A severe weather outbreak struck the Southeastern United States on February 15, with large hail, damaging winds, and five tornadoes affecting five states. An EF2 tornado destroyed two homes and damaged trees in and northeast of Damascus, Georgia, injuring five people. A more destructive high-end EF3 tornado struck the Ocean Ridge Plantation neighborhood near Sunset Beach, North Carolina, causing major damage to many homes, some of which were leveled or swept away, before moving into rural areas and damaging or snapping hundreds of trees. This tornado killed three and injured 10.
In Memphis, Tennessee, the city declared a state of emergency on February 17, after the city saw a record daily snowfall accumulation of 5.7 in (14 cm), bringing the total snowfall since February 15 to 10–12 in (25–30 cm). The heavy snowfall disrupted FedEx operations at its Memphis hub, which hampered COVID-19 vaccine distribution nationally. On February 18, Memphis's public utility MLGW issued its first ever boil water order as water pressure levels dropped, affecting 260,000 households. The boil water order was lifted on February 25.
The winter storm strained the power grids in northern Mexico, leading to cascading blackouts for 4.7 million homes and businesses in Mexico.
Temperatures as low as −18 °C (0 °F) were recorded, as shortages of natural gas led to blackouts in Nuevo León, Coahuila, Tamaulipas, and Chihuahua along the border with Texas. Over a dozen people died in Ciudad Juárez, Chihuahua; Río Bravo and Matamoros, Tamaulipas; and Monterrey, Nuevo León; due to the winter storm. President Andrés Manuel López Obrador (AMLO) said on February 17 that Mexico would increase the use of oil and coal to produce electricity, as well as purchase three shiploads of natural gas to deal with power shortages. He also warned that periodic local outages would continue through February 21. Local authorities mentioned that no hospitals had been left without electricity at any time.
In Ontario, snowfall warnings were issued in advance of the winter storm. Buses were cancelled across the Greater Toronto Area, and schools were completely closed in Halton and Durham. 20 cm (7.9 in) of snow fell in Windsor, 12 cm (4.7 in) at Toronto Pearson International Airport and 18 cm (7.1 in) fell in Ottawa. The highest totals in the region were the over 30 cm (12 in) in and Hamilton and Niagara Region.