Houston was spared from an ice storm and avoided the most severe impacts of the weekend winter storm.
Early forecasts predicted freezing rain and widespread ice accumulation, but the worst-case scenario did not materialize in the city core.
Precipitation largely fell as rain while surface temperatures stayed at or just above freezing. Colder air arrived overnight, but by then most of the moisture had moved out.
The result: Lighter icing than expected, especially in Houston proper. Isolated slick spots and icy bridges formed in areas where temperatures dipped below freezing, while north and west suburbs saw more ice and sleet.
KPRC 2 Meteorologist Justin Stapleton spoke with Jeff Lindner, director of Hydrologic Operations and meteorologist for Harris County Flood Control District, about why Houston didn’t experience worse conditions.
Justin Stapleton: Right, and Jeff, one of the things folks have been asking me, and we were chewing this over in the weather department, is that yesterday (Sunday), as the storm moved through, temperatures were cooling but we didn’t have truly cold air in place during the heaviest precipitation. You mentioned around 5 o’clock that your crews were out checking overpasses, flyovers, and such, and even those surface temperatures were running a little above 32°F.
Do you think that’s what helped us avoid the worst-case scenario with much heavier ice accumulation?
Jeff Lindner: I think there are a couple of key reasons. First, those ramps and connectors were a bit warmer than the ambient air temperature, so we really needed to get down into the mid-20s to start seeing significant issues there. Second, and this gets a little meteorological, the air temperature around 3,000 feet was 40–42°F. So even though the surface was cold, the rain falling from above was relatively warm. It took time for those droplets to cool enough to reach the freezing point on contact. A few factors worked in the city’s favor, sparing Houston proper from major ice. Of course, farther north and west where it was colder at the surface, we did see more ice accumulation.
Why the City Was Spared Winter precipitation type depends on the vertical temperature profile in the atmosphere.
Here’s what made the difference:
- Warm layers aloft, called a “warm nose,” melt falling snow into rain. The depth and strength of these warm layers determine whether precipitation stays as rain, changes to sleet, or becomes freezing rain.
- Shallow cold layer near the surface lets supercooled rain droplets freeze on contact → causing freezing rain (and ice buildup).
- Deeper cold air near the surface favors sleet or snow instead. In Houston’s case, the combination of warmer air aloft + marginal surface cold + timing of the heaviest rain kept major ice accumulation from happening in the urban core.