The First Major U.S. Snow Load Overhaul in 30 Years Is Reaching Job Sites: What Roofing Contractors Need to Know

January 2026 gave the industry a blunt reminder of what winter does to roofs. Early modeling put insured losses from Winter Storm Fern at up to $4 billion, with losses in a number of states each potentially exceeding $50 million, placing Fern among the costliest U.S. winter storms on record.

The roof-level view was just as pointed. Early data for the first quarter of 2026 pointed to tens of thousands of ice, snow, and collapse claims tied to that winter's storms, with reconstruction costs continuing to climb even as overall claim volume fell.

Against that backdrop, a structural code change that most roofing contractors have not read is quietly reshaping how snow gets designed for on every project they bid.

What Actually Changed in ASCE 7-22

ASCE 7-22 is the referenced load standard behind the 2024 IBC and 2024 IRC. For snow, the revisions are not cosmetic.

Strength-based ground snow loads. Earlier editions used ground snow loads based on a 50-year mean recurrence interval, then multiplied by 1.6 in strength design. ASCE 7-22 switched to reliability-targeted design ground snow loads, adopted because roofs designed to the old 50-year value were achieving inconsistent reliability across different parts of the country.

The load factor is gone. Under the new approach, the strength design snow load factor drops from 1.6 to effectively 1.0, and a 0.7 factor converts strength-level values back for allowable stress design. This is one of the most common sources of error in the transition. Pulling a ground snow load value from the new maps and running it through an old load combination overstates or understates the design load depending on which direction the mistake runs.

Maps by Risk Category. The 2024 IBC now points to reliability-targeted ground snow load values with separate figures for each Risk Category, backed by a geocoded database rather than a single national map. The underlying dataset reflects roughly 25 additional years of snow data and revised estimation procedures.

Higher floor for low-slope roofs. Minimum snow load for Risk Category II low-slope roofs moved from 20 psf to 30 psf.

A new winter windiness variable. ASCE 7-22 introduces a mapped parameter accounting for winter wind, since areas with identical ground snow loads can experience very different winter winds, which changes drift heights. Thermal factors were revised as well.

Adoption Is a Patchwork, and That Is the Practical Problem

There is no single national switch-on date. The 2024 IBC has been adopted or is in process across a wide set of jurisdictions, including Colorado, Illinois, Iowa, Nevada, New Hampshire, New York State, North Dakota, Oregon, South Dakota, Texas, Utah, and Wyoming, alongside a number of major municipal adoptions.

Meanwhile, some states still operating under the 2021 IBC had already adopted ASCE 7-22 ahead of the model code cycle. Others are working to a fixed future date, with some states not scheduled to implement the 2024 IBC until 2027.

For a contractor working a single metro, this is a footnote. For anyone bidding across state lines, or for a distributor supplying contractors in several states, it means the snow number on a drawing may be derived from two entirely different standards depending on which county it came from. Two projects with the same ground snow load on paper can carry materially different design intent.

Why This Lands Harder on Metal and Steep-Slope Work

The code change arrives while metal roofing is taking share of the residential market, with industry forecasts pointing to continued growth in metal roofing shipments through the next several years.

Metal sheds snow. That is a selling point right up until the snow releases in a slab over an entrance, a walkway, a parked vehicle, a lower roof, a gutter run, or rooftop equipment. Slippery-surface roofs concentrate a liability that textured roofing largely diffuses, and the code revisions around drift, unbalanced load, and sliding snow are precisely where designers now have more explicit guidance, and more exposure if it is ignored.

Two structural realities follow for anyone installing on standing seam, exposed fastener, or synthetic tile and shake systems:

• Sliding snow is a design condition, not a warranty footnote. Where snow retention is used to hold load on the roof, that load stays on the structure, and it must be reconciled against the new strength-based numbers rather than assumed away.
• Attachment method is now a documentation issue. Clamp-to-seam versus penetrating attachment, spacing, row count, and panel gauge all feed the calculation. Defaulting to a familiar layout is not a defensible position in a jurisdiction that has moved to ASCE 7-22.

Four Things to Do Before Your Next Winter-Region Bid

1. Confirm the governing standard with the authority having jurisdiction, not the plan set. Ask which ASCE 7 edition applies, since local amendments routinely diverge from the IBC year alone.
2. Use the ASCE Hazard Tool. It returns ground snow load by address and Risk Category, including allowable stress design values, and it is referenced directly in both the IBC and IRC.
3. Re-check any reusable detail library. Standard details built against ASCE 7-16 assumptions, especially snow retention layouts and drift details at parapets, dormers, and roof steps, need to be re-derived, not carried forward.
4. Put the calculation in the file. With reconstruction costs rising and claim severity elevated, documented load calculations are the difference between a supported repair recommendation and a disputed one.

The Bigger Signal

Codes lag reality by design. The fact that snow provisions were rebuilt around reliability rather than a fixed recurrence interval, after documented shortfalls in regions where the old numbers ran short, points to where the standards bodies think the risk actually sits. Contractors and distributors who understand the new baseline before their competitors do will be the ones writing accurate bids while everyone else is re-pricing mid-project.