Winter Storm Showdown: Uri (2021) vs. Fern (2026)
Animated temperature timelapse maps reveal how Uri’s historic freeze dwarfed Fern in duration and severity
Winter Storm Uri (February 2021) and Winter Storm Fern (January 2026) are two of the most significant winter weather events to strike the southern United States in recent memory. Both involved polar vortex disruptions pushing Arctic air deep into the continental U.S., but the two storms differ dramatically in duration, severity, and ultimate impact. This interactive analysis uses animated timelapse maps to compare the day-by-day temperature progression of each storm, with a focus on how long different regions endured below-freezing conditions.
Uri (2021) vs. Fern (2026)
Side-by-side temperature timelapse and freezing duration analysis
Storm profiles
Winter Storm Uri (February 13–19, 2021)
Uri was the costliest winter storm in U.S. history. An unusually severe polar vortex disruption drove Arctic air deep into Texas and the southern Plains, producing temperatures 40–60°F below normal across a region unaccustomed to sustained cold.
The defining feature of Uri was duration. Dallas spent 139 consecutive hours below freezing. Waco set an all-time record of 205 hours. Austin broke its record at 164 hours. This extended siege overwhelmed building insulation, caused catastrophic pipe bursts, and—most critically—collapsed the Texas power grid. At peak, 4.5 million customers lost power for an average of 42 hours. The cascading infrastructure failure killed 246 people and generated approximately $15 billion in insured losses.
Winter Storm Fern (January 23–27, 2026)
Fern was among the most geographically expansive winter storms in recent memory, stretching over 2,000 miles from the Texas-Mexico border to Maine and affecting 24+ states. The storm prompted emergency declarations across the country and placed over 230 million Americans under winter weather alerts.
While Fern brought genuinely dangerous cold to Texas—Dallas dropped to 9°F, breaking an 86-year-old record—it was materially less severe than Uri in two critical respects: temperature (10–20°F warmer at peak) and duration (5 days vs. 7, with roughly half the consecutive below-freezing hours). Fern’s primary hazard in the Deep South was ice accumulation, with Mississippi experiencing its worst ice storm since 1994.
The duration difference
The animated timelapse above makes the key distinction clear: Uri didn’t just get colder, it stayed cold much longer. This matters enormously for insured losses:
Frozen pipes are the dominant claim type in winter storms, accounting for 80–90% of homeowner claims. Pipes burst not from a single cold night but from sustained exposure that overwhelms insulation. Uri’s 139–205 hour freeze duration in Texas cities was roughly 2–4x longer than Fern’s 48–65 hours.
Power grid failure compounded Uri’s damage. Without electricity, buildings lost heating entirely, accelerating pipe freeze-through. During Fern, the Texas grid held stable—ERCOT now has 17,000 MW of battery storage online (vs. zero in 2021) and mandated natural gas weatherization.
Ice dam formation requires sustained cold to allow ice buildup on roofs. Uri’s multi-day freeze created far more severe ice dam damage than Fern’s shorter cold window.
Snowfall and ice: different hazards
The two storms had distinctly different precipitation profiles:
| Metric | Uri (2021) | Fern (2026) |
|---|---|---|
| TX snowfall | Heavy (Abilene 14.8”, Austin 6.4”) | Moderate (DFW 3.3”, Austin ~2”) |
| Southern ice | Moderate (0.1–0.25” in Houston) | Severe (1.0” in Oxford, MS; 0.75” Nashville) |
| NE snowfall | Minimal | Heavy (Boston 16.7”, Pittsburgh 11.2”) |
| Primary southern hazard | Snow + extreme cold | Ice accumulation |
Fern’s ice storm in the Deep South—particularly Mississippi and Tennessee—was catastrophic for trees and power lines but generated a different loss profile than Uri’s snow-and-freeze combination. Nashville alone saw 189 broken utility poles and 290,000 customers without power.
Insurance implications
Loss comparison
| Uri (2021) | Fern (2026) | |
|---|---|---|
| Insured losses | ~$15 billion | $1–2 billion (est.) |
| Primary claims | Frozen pipes (TX) | Ice damage (South), frozen pipes |
| Claim count | 500,000+ (TX alone) | TBD |
| Grid-related losses | Massive (business interruption, spoilage) | Minimal |
Why losses differ by 10x
The order-of-magnitude difference in insured losses between these storms comes down to three factors:
- Freeze duration: Uri’s 2–4x longer below-freezing periods caused exponentially more pipe damage
- Grid failure: Uri’s power collapse multiplied losses through business interruption, additional living expenses, and accelerated building freeze-through
- Temperature severity: Uri’s sub-zero readings in Texas exceeded building design limits; Fern’s single-digit lows were severe but within a range many structures can withstand temporarily
Forward-looking considerations
For property-casualty insurers and reinsurers, the Uri-Fern comparison offers several lessons:
Duration is the key variable for winter storm loss modeling, not just minimum temperature. A storm that maintains 20°F for a week can generate larger losses than one that briefly touches 0°F.
Grid resilience reduces tail risk materially. Texas’s $8+ billion investment in weatherization appears to have prevented a second $15 billion event. This should be reflected in catastrophe model calibrations.
Geographic shifting of winter storm risk. Fern’s heaviest impacts hit the Deep South (ice) and Northeast (snow) rather than Texas. Insurers should monitor whether polar vortex disruptions are producing more varied geographic footprints.
Ice storm losses are growing. Fern’s ice accumulation in Mississippi and Tennessee caused severe infrastructure damage. As the insurance industry tends to focus on snow and freeze, ice-specific exposure assessment may warrant greater attention.
Data sources
- NWS Fort Worth – Feb 2021 Historic Winter Storm
- NWS Houston – Valentine’s Week Winter Outbreak 2021
- NOAA/NCEI – The Great Texas Freeze
- Oklahoma Mesonet – Historically Frigid February
- Wikipedia – January 2026 North American winter storm
- AccuWeather – $100B+ Fern damage estimate
- Texas Department of Insurance – Uri loss data
- PowerOutage.us – Real-time outage tracking
- ERCOT – Texas grid status
For the full Winter Storm Fern analysis, see Winter Storm Fern: Analyzing the Historic January 2026 Freeze.