2023 South Central Texas Ice Storm

Confidence in freezing drizzle and/or light freezing rain over portions of Central Texas, including Hill Country, begins to increase. NWS Austin/San Antonio begins to message a freezing rain threat spanning Jan 31 through Feb 2 in its public-facing forecasts. Still beyond the range covered by high resolution model guidance, the southern extent of the freezing rain potential remains unresolved.

With long-range high-resolution model guidance beginning to become available, freezing rain potential continues to appear possible, primarily over Hill Country and the higher terrain of western Travis and Williamson counties. A Winter Storm Watch is issued.

The Arctic cold front reaches Burnet, Llano, and Williamson counties, pushing south-southwest through the remainder of South-Central Texas through midnight. Temperatures plummet behind the boundary, as most locations see a twenty to forty degree temperature drop over a six to nine hour period.

With the icing event now within the range covered by the majority of the high-resolution models, it becomes clear that periods of freezing rain and potential icing impacts will be possible farther south and east than initially forecasted. The previous Winter Storm Watch is upgraded to a Winter Storm Warning. A Winter Weather Advisory is issued east of the warning. With light freezing rain appearing possible as early as the afternoon hours on Jan 30, NWS Austin/San Antonio advises that travel will become hazardous across Hill Country and the Interstate 35 corridor within the next twenty-four hours. Power outages appear probable and are introduced into the warning and advisory messages with this statement: "Prepare for possible power outages."

With updated high-resolution model guidance arriving, confidence in a significant icing event across Hill Country, the Interstate 35 corridor, and portions of the Coastal Plains continues to rise. Forecasted ice accumulations continue to trend upward for Hill Country and the Austin metropolitan area, with the overnight update indicating the potential for one quarter to one half inch of ice buildup by the conclusion of the event. Additional counties are added to the Winter Storm Warning and Winter Weather Advisory. NWS Austin/San Antonio states that travel will become extremely hazardous within the next twelve to eighteen hours across Hill Country and the Interstate 35 corridor, with non-emergency travel being discouraged. Motorists are reminded that elevated bridges, overpasses, and flyover ramps will be the first surfaces to ice over. Power outage potential continues to be a primary concern. The NWS Austin/San Antonio Winter Storm Warning for the Hill Country and Austin metro area states: "Numerous power outages possible."

Surface temperatures drop to freezing across portions of Hill Country and the I-35 corridor. The majority of the Austin metro falls to and just below 32 degrees within the next three to six hours.

Freezing rain begins to fall over Hill Country and portions of the Interstate 35 corridor. No major impacts occur, though reports of light ice buildup on tree branches, traffic signs, and other elevated surfaces are received by NWS Austin/San Antonio.

The updated afternoon forecast reiterates many of the messages emphasized in the previous package. With temperatures expected to remain at or below freezing through mid-day February 2 in Hill Country and portions of Travis and Williamson counties, 48-60 hours of icing potential appears probable over the coming days. Several hourly updates on the approximate surface freezing line location begin to be shared on social media.

Periods of light freezing drizzle and freezing rain continue over Hill Country and the Interstate 35 corridor. Impacts begin to occur in the Austin metro, where multiple flyover ramps are shut down due to icing. A multi-vehicle car accident occurs at the Ben White Blvd onramp to Interstate 35 near downtown Austin. One person is tragically killed.

Forecasted ice accumulations continue to increase for Hill Country and portions of the I-35 corridor ahead of the main icing event, where one half to three quarters of an inch of buildup are beginning to appear likely. Up to one tenth of ice accumulation now appears possible in the immediate downtown San Antonio area, and as far south as portions of the Coastal Plains. The Winter Storm Warning and Winter Weather Advisory are expanded south. For the first time since the 2021 winter storm, the purple “high” impact category is used in the NWS Austin/San Antonio 5 Day Planner graphic. The NWS Austin/San Antonio Winter Storm Warning for the Hill Country and Austin metro area continues to state: "Numerous power outages possible."

The forecast picture finally begins to stabilize for the event. Confidence in a nocturnal episode of heavy freezing rain over portions of Hill Country and the Interstate 35 corridor during the predawn hours on Feb 1 is now high. Previous impact and safety messages continue to be reiterated. Motorists are urged to remain in their vehicles until first responders arrive if they are involved in an accident. The NWS Austin/San Antonio Winter Storm Warning for the Hill Country and Austin metro area continues to state: "Numerous power outages possible."

As forecasted, a region of moderate to heavy freezing rain develops southwest of San Antonio, ultimately progressing into portions of the Interstate 35 corridor and Hill Country, including the entirety of the Austin metro and northern San Antonio suburbs. Precipitation falls so heavily that warmer air from above the surface mixes to ground level. This allows surface temperatures to rise into the 31-33 degree range along most of the I-35 corridor, likely preventing catastrophic travel disruptions across the region. Elevated surfaces remain below freezing, however, leading to rapid ice accumulations on tree branches, power lines, and traffic signs. Trees begin to give out under the added weight of the ice buildup, falling onto cars, houses, and electrical lines. Power outages become numerous across this portion of the area, with the total exceeding 200,000 customers in the Austin metro area. Emergency Managers report several side roads impassable due to fallen trees.

The Storm Prediction Center issued a Mesoscale Discussion highlighting rain and icing impacts along the Interstate 35 Corridor from San Antonio and into metro Austin: "As of 0745 UTC, regional radar analysis showed intensifying freezing rain showers across portions of southern and central TX. Driven primarily by low and mid-level warm advection, these showers have intensified over the last 90 minutes coincident with surface temperatures falling to near or below freezing. Recent reports of freezing rain in the San Antonio Metro and I-35 corridor suggest freezing precipitation rates have increased to near 0.1-0.15 in/hr with the more intense showers. While the heaviest precipitation will be intermittent, additional development farther southwest, evident from new radar echos and hi-res guidance, suggests multiple rounds of moderate to locally heavy freezing rain are likely through early this morning. As additional showers develop and shift northeastward with time, slightly cooler surface temperatures in the upper 20s F may favor more efficient ice accretion and some potential for sleet. With multiple rounds of moderate to locally heavy winter precipitation expected, there exists the potential for significant icing impacts along the I-35 corridor in central TX through early this morning."

With heavy freezing rain ongoing over parts of Hill Country and the Interstate 35 corridor, previous impact and safety messaging continue. Graphics on staying warm during power outages are shared.

Daylight reveals the extent of large tree branches and power lines down throughout the region. Power outages are numerous across the area, with the total exceeding 200,000 just in the Austin metro area alone.

Several counties in the Coastal Plains and southern Edwards Plateau have either climbed above freezing or will within the next several hours. The Winter Storm Warning and Winter Weather Advisory are cancelled for those southern counties that are above freezing.

Additional information is shared on safety tips during a power outage.

Given ongoing surface temperature trends and high confidence in a final round of moderate to heavy precipitation during the overnight period, the Winter Storm Warning is extended into the morning of Feb 2 for the Hill Country and Austin metro area. It is in this region where freezing surface temperatures will be most widespread. The warning is downgraded to a Winter Weather Advisory for remaining counties. The potential for additional downed trees and power outages continues to be a point of emphasis in public messaging in the warning area.

As anticipated, one more batch of moderate to heavy rain and freezing rain impact Hill Country and the Interstate 35 corridor. The activity resembles that of thunderstorms in radar data as strong upper level forcing passes overhead. Despite the heavy precipitation rates, impacts aren’t nearly as severe as they were in the early Feb 1 round of freezing rain.

With the final round of moderate to heavy freezing rain ongoing, the last situation report is issued to our core academic, emergency management, and media partners. Despite the concluding freezing rain potential, the continued potential for downed trees and power outages is highlighted.

The Winter Weather Advisory is canceled as temperatures are above freezing and ice melted.

The Winter Storm Warning is canceled as temperatures are above freezing and ice melted.

Over 200,000 customers in Travis and Williamson Counties (Austin metro area) still remain without power.

Power is gradually restored across the region.

As of February 16, 2023 close to 35,000 tons of storm debris had been collected in the Austin metro area by almost 5,000 truckloads. Austin collected more tree debris in just one week of collection than the entire tonnage weighed from the 2021 winter storm. Collection of storm debris was expected to continue through the end of April.