While climbing temperatures are a welcome reprieve for the hundreds of thousands of Texans struggling to keep warm, it comes at a price. Dramatic temperature swings can be notoriously challenging for infrastructure.
Snow and ice falling from buildings can be dangerous, while refreezing moisture on roadways could transform them into a sheet of ice. Potholes could form on area roadways, too. Meanwhile, more water main breaks and bursting pipes are likely.
Cold lingers Friday, but it’s the beginning of the end
Before the thaw begins in earnest this weekend and next week, record cold persisted Friday in parts of the Southern Plains, which continued to deal with power outages and widespread damage stemming from burst pipes and water main breaks.
Oklahoma City dropped to 3 degrees early Friday morning, breaking the record low of 7 set in 1903. Lawton, Okla., home to Fort Sill, fell to zero.
In Texas, Austin, Victoria and Abilene all set records as well, falling to 20, 24, and 5 degrees, respectively.
Improvement was in the works Friday, though, when Waco, Tex., was expected to hit 36 degrees for the high. That would be its first time since Feb. 10 to hit freezing. The city broke its record for longest freezing stretch, beating out 190 hours in January 1948. Waco had made it up to 78 degrees earlier this February.
In Dallas, a still-chilly high of 35 degrees was forecast Friday, with the mid-40s in Houston. These temperatures are still about 20 to 25 degrees colder than normal.
There is an end in sight, however. Friday night will be the last with dangerously cold temperatures, with the cold easing Saturday into Sunday.
Dallas was forecast to drop to 22 degrees Friday night; Saturday night’s low will be closer to 44 degrees. In Austin, those numbers were 23 degrees Friday night and 38 on Saturday night, while Saturday night’s low in Houston will be 20 degrees warmer than Friday night’s.
Thaw to commence this weekend
Across the Panhandle and west Texas, the cold was already being scoured out by breezy southwesterly winds. Amarillo, which spent an entire week below 22 degrees, was looking at a projected high of 55 Saturday. The city hit minus-11 Monday morning and never made it above 7 degrees. Highs near 70 are expected by Tuesday, highlighting the meteorological caprice inveterate to the Plains.
In Dallas, Saturday should see temperatures peak around 45 degrees, and Sunday near 55 degrees. By Tuesday, mid-60s are possible, with temperatures flirting with 70 by the middle of next week. Overnight lows next week should be greater than the highs most of this week.
Houston is forecast to see high temperatures warm from the mid-50s Saturday to mid-60s Sunday and could also see 70 degrees by Tuesday.
The only remaining subzero readings Saturday should be in Minnesota, Wisconsin and the northern fringes of eastern Iowa and Illinois. That’s where the air mass’s icy clasp won’t go down without a fight as the core of the cold gets yanked back into Canada. By Sunday, any negative readings vanish from the map completely.
Impacts from the thaw
The warm-up, albeit somewhat gradual in the Southern Plains, will bring renewed issues in what’s already been a taxing situation. Melting snow and ice falling from trees and rooftops could be dangerous, particularly from high-rise buildings in city metro areas.
With overnight temperatures still slated to drop below freezing Friday, too, additional issues associated with refreezing could arise.
“Mainly the impacts we’re expecting is refreezing of anything that turns into slush,” said Sarah Barnes, a meteorologist at the National Weather Service in Fort Worth. “That could cause some hazardous travel conditions. We’ll see freezing temperatures across north and Central Texas [Friday night]."
Dallas has a snow depth of four inches, meaning there’s about a half inch or more of liquid water equivalent trapped in there. That will all melt in the coming days, potentially refreezing on roadways at night.
Moreover, pipes — a large number of which have already burst in the freezing weather — are once again at risk from the temperature swing.
“As we start to thaw out, we’re going to see more broken pipes and water main breaks,” Barnes said. “Just with everyone’s pipes starting to thaw out again, we’ll see plenty more of that.”
Potholes in roadways will be an issue, too, as many Upper Midwesterners and New Englanders know all too well.
“They are caused by the expansion and contraction of ground water after the water has entered into the ground under the pavement,” wrote B. Alan Brubaker, an engineer working for Summit County, Ohio, on his website. “If [water] has a chance to freeze, it will take up more space under the pavement, and the pavement will expand, bend, and crack, which weakens the material pavement.”
Eventual melting of the water in turn permits the pavement to contract, leaving gaps beneath it that more liquid water can enter. This makes the pavement weaker when vehicles pass over it, and, if temperatures freeze once again, the cycle repeats.
Given that much of North Texas will experience a hard freeze Friday night, lows above freezing Saturday night and then a return to freezing temperatures Sunday night, the repetitive cycles could prove damaging to area roadways.
In the longer term, a return to above-average temperatures is forecast next week. The Weather Service Climate Prediction Center is calling for seasonable conditions on the Plains and mild temperatures in the East from the end of February into March.
Deeper into March, much of the South, including Texas, will be favored to experience unusually mild springtime warmth.