Winter Storm Fern Poses Nationwide Energy Test

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Written by Aaron Studwell, Ph.D., Energy Meteorologist & Analyst, for IIR News Intelligence (Sugar Land, Texas)

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Summary

Winter Storm Fern, a long-duration weather event, could amplify power outages, strain the energy infrastructure, and slow recovery across large portions of the United States.

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Fern's Impact

Winter Storm Fern's impacts have been dominated by two things: the scale of the power disruptions and the way cold air behind the storm was slowing recovery. By Sunday afternoon, multiple media reports citing PowerOutage.us indicated roughly one million customers were left without power across a wide swath of the South and East, with Tennessee among the hardest hit states.

The pattern is consistent with an ice-driven outage event: freezing rain adds weight to lines and vegetation, trees fall into distribution networks, and repairs often require field crews to physically rebuild components rather than simply re-energizing a tripped circuit. This combination of factors extends restoration timelines, especially when roads are impassable and temperatures remain below freezing.

Those outages are not just a public safety problem; they also become an energy system problem. Fern aligned high heating demand with operational constraints. Reuters reported that in PJM Interconnection--serving roughly 67 million people in the eastern U.S.--nearly 21 gigawatts of generation capacity was offline on Sunday, and that constrained natural gas supply and pipeline limitations contributed to the strain.

Sharp wholesale power-price spikes, including peaks over $1,800 per megawatt hour (MWh) in parts of Virginia, reflecting the tight balance between demand, available generation, and deliverability. In New England, there was a shift toward oil generation as natural gas constraints intensified during the cold.

But as of Monday afternoon, only two U.S. refineries had reported significant unplanned outages as a result of the storm, according to IIR Energy's Breaking Energy News (BEN). These included Cenovus Energy's (Calgary, Alberta) 172,000-barrel-per-day refinery in Lima, Ohio, and Calumet Specialty Products Partners' (Indianapolis, Indiana) 60,000-BBL/d refinery in Shreveport, Louisiana.

Subscribers to Industrial Info's Global Market Intelligence (GMI) Petroleum Refining Plant Database can view profiles of the Lima and Shreveport refineries.

Development

Winter Storm Fern was not the result of a "one and done" storm system. It resulted from the combination of a major Arctic outbreak that first pushed deep cold air southward. The cold air intrusion locked sub-freezing temperatures in place across much of the central and eastern U.S. Later in the week, a storm system moved out of the southern High Plains and into Texas. A stream of warm Gulf air moving north ahead of the low, clashed with entrenched cold air to produce widespread snow, sleet, and freezing rain.

On Thursday, a strong ridge over central Canada pressed southward into the Plains, ushering in bitterly air. By Friday, this Arctic air mass moved across the Plains, upper Midwest and across the Great Lakes. Meanwhile, an increasingly active southern jet stream brought Pacific moisture and upward lift to the Four Corners region. This combination--cold air at the surface and copious moisture aloft--set the stage for a long corridor of snow, sleet and freezing rain.

With Fern developing further north than the early outlook, the forecast track also shifted poleward. This development allowed warm Gulf moisture to move further north than originally forecast.

In winter storms, this matters because the "warm nose" a few thousand feet above the ground can melt falling snow into rain before it refreezes at the surface. When that happens, the difference between heavy snow and an ice storm can come down to a narrow corridor only a few counties wide.

The net effect of the northward trend was a poleward shift in the main precipitation shield and a northward adjustment in where the biggest snow totals were most likely, while the ice corridor remained a dominant hazard on the storm's southern flank.

By Friday, Fern was defined as much by its forecasted duration and geographical extent, as by peak intensity. Snow expanded from the southern Rockies and High Plains into the central Plains and Mid-South, while a broad corridor of freezing-rain and sleet evolved from Texas into the ArkLaTex region and east toward the Tennessee Valley.

In several metro areas, the narrative was the transitions from snow to sleet to freezing rain (or the reverse) as the storm's track and structure evolved. Repeated transitions matter as they compound impacts with inches of sleet on top of fresh-fallen snow. As the sleet changes to freezing rain, it coats the existing snowpack, developing a hard crust. Additionally, freezing rain will accumulate on trees and power lines, potentially leading to catastrophic failure.

By Sunday, the national outlook was locked in. Heavy snow fell from the Ohio Valley to the Northeast and a catastrophic ice storm from the Lower Mississippi Valley, across the Southeast, and into the Mid-Atlantic. As a low-pressure center moved from the central Gulf Coast to the mid-Atlantic, a secondary low along the Southeast coast. The coastal low then tracked northeast toward southern New England before exiting into the Atlantic. This two-low evolution broadened the storm's precipitation shield and sustained lift over the same regions for many hours.

This pattern also favored cold-air damming east of the Appalachians, playing a decisive role in the precipitation pattern. When cold air is "dammed" against the Appalachians, surface temperatures can remain at or below freezing even while warmer air flows overhead. This was an ideal recipe for freezing rain in places that do not often see long-duration ice.

At the same time, the southern edge of the storm featured slight risk for severe storms along the central Gulf Coast. The forecasted hazards included damaging wind gusts and tornadoes. (There were 71 separate wind reports to the National Weather Service's regional offices, with reports of wind in excess of 70 miles per hour.) The warm sector near the Gulf can support severe storms even while ice and snow are occurring only a few hundred miles to the north.

In short, Fern's development was a layered, evolving system--Arctic air first, then a Gulf-fed storm tracking northeast, then a coastal phase that kept precipitation going in the East. The biggest forecasting challenge was not whether a major storm would happen, but exactly where the rain-ice-snow boundaries would set up, and how long each region would remain locked into the most damaging precipitation type.

Snow totals and ice amounts varied sharply by region, but the overall footprint was immense. A heavy snow corridor from the Ohio Valley into the Northeast left these regions under daily record totals. Louisville, Kentucky, and Cincinnati, Ohio, each reported 8 to 9 inches, while Dayton, Ohio, received a foot on snow. Across the Washington, D.C. metro area, there was up to a foot on snow, and sleet also impacted the area. Further north, Central Park in New York City received a foot of snow, while snowfall at Boston's Logan Airport exceeded 18 inches.

Click on the image at right for a Pivotal Weather snowfall map of the eastern U.S.

The cold air behind Fern is the factor that turns a disruptive winter storm into a prolonged infrastructure event. Frigid temperatures are likely to persist across a broad swath of the central and eastern U.S. through the week, with many areas staying below freezing for daytime highs. These conditions can reduce mobility, slow repairs, and keep snow and ice from melting off roads, roofs, and lines. These wintry conditions also sustains elevated heating demand, raising the risk of additional stress if new outages occur or if fuel supply remains constrained.

Daniel Graeber contributed to this report.

Key Takeaways

• Fern developed as a major Arctic outbreak interacted with an active southern jet, creating an extensive corridor of snow, sleet, and freezing rain rather than a single fast-moving event.
• A northward shift in the storm track allowed warm air aloft to push farther north, increasing early forecast track uncertainty.
• Precipitation-type transitions impacted many regions, with sleet and freezing rain accumulating on snowpack, trees, and power lines, raising the risk of structural and grid failures.
• Ice-driven power outages exceeded one million simultaneous outages, while extreme cold and fuel constraints stressed power generation, transmission and natural gas supply.

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About IIR News Intelligence
IIR News Intelligence is a trusted source of news for the industrial process and energy markets, powered by Industrial Info Resources' Global Market Intelligence (GMI).

About Industrial Info Resources
Industrial Info Resources (IIR) is the leading provider of industrial market intelligence. Since 1983, IIR has provided comprehensive research, news and analysis on the industrial process, manufacturing and energy related industries. IIR's Global Market Intelligence (GMI) helps companies identify and pursue trends across multiple markets with access to real, qualified and validated plant and project opportunities. Across the world, IIR is tracking over 250,000 current and future projects worth $30.2 Trillion (USD).