New Hampshire Ground Snow Load by County and Town

New Hampshire adopted a snow load study, and that study carries the values, Ground Snow Loads for New Hampshire (ERDC/CRREL TR-02-6), through U.S. Army Corps of Engineers, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory (CRREL), with Structural Engineers of New Hampshire Inc. (SENH). twelve of its published figures are set out below with the row each was read from. Only 14 states out of 50 publish anything of their own like it; the other 36 send a reader either to the national code or to a county counter. twelve New Hampshire figures, running from 50 lb/ft2 at Portsmouth to 120 lb/ft2 at Beans Purchase, every one of them quoted from the document it was printed in. Nationally 235 figures were read across 33 states.

Local enforcement agency of the municipality, under the New Hampshire State Building Code: the town or city code office applies the statewide table, and the study's own elevation adjustment is what moves the number inside one town. In its own words: “"Local enforcement agency" means, for a municipality as defined in RSA 155-A:1, XI that has adopted an enforcement mechanism under RSA 155-A:3, the official qualified and authorized to issue permits, make inspections, and enforce the laws, ordinances, and rules enacted by the state and local government that establish standards and requirements applicable to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal, and demolition of every building or structure, or any appurtenances connected or attached to such building or structure.”

Part of New Hampshire is a case study area, meaning the published document expressly declines to give those places a figure and sends the designer back to the local building department for one. 16 states carry a rule like this, and it is the commonest reason a search for a single number comes back empty. The rule reads: “Do not use this information above 2500 ft: Conduct a site-specific snow load case study.”

The figure moves with elevation in New Hampshire, which is the hardest case for a reader: two houses a mile apart and a thousand feet apart take different numbers, and 13 states are keyed this way. The published New Hampshire figures run from 50 lb/ft2 to 120 lb/ft2.

State of New Hampshire, RSA 155-A (New Hampshire Building Code), as reviewed and recommended by the State Building Code Review Board adopts International Building Code (2024). New Hampshire amended it rather than adopting it whole, and 22 states have done the same. The adopting rule reads: “"New Hampshire building code" or "state building code" means the adoption by reference of the International Building Code 2024, the International Existing Building Code 2024, the International Plumbing Code 2024, the International Mechanical Code 2024, the International Energy Conservation Code 2018, the International Swimming Pool and Spa Code 2024 and the International Residential Code 2024, as published by the International Code Council Inc., and the National Electrical Code 2023, as published by the National Fire Protection Association, Inc., as reviewed and recommended by the state building code review board, including all amendments reviewed and approved by the board as of October 10, 2025, and ratified by the legislature in accordance with RSA 155-A:10, and any errata issued by the model code organization, or amendments informed by such errata, as approved by the board.”

A ground snow load is a weight per unit area and not a depth, and the two are joined only by the density of the snow on the day, which is why the published documents give the load and leave the depth out. Wet spring snow and dry January snow of the same depth are different weights on the same roof. Local enforcement agency of the municipality, under the New Hampshire State Building Code works in loads for that reason, and so does every figure set out below.

The New Hampshire document itself is the place to look a town up, and what it prints is applied by Local enforcement agency of the municipality, under the New Hampshire State Building Code. The document behind it is Ground Snow Loads for New Hampshire (ERDC/CRREL TR-02-6), published by U.S. Army Corps of Engineers, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory (CRREL), with Structural Engineers of New Hampshire Inc. (SENH), read on September 23, 2026. It establishes the point this way: “Since these case studies have been done according to the requirements of ASCE 7-98, it is appropriate to use the values in this report for all places in New Hampshire. In other words, for places in New Hampshire where ground snow loads can be determined from the map in ASCE 7-98, the values in Table 1 supersede those values.”

14 of 50: Connecticut, Indiana, Maryland, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New Jersey, North Carolina, Rhode Island, Utah, Vermont, Wisconsin. The other 36 split into 17 that adopt the national code without a snow amendment and 19 that leave every figure to a county or city building department. That is the single most useful fact about this subject and no one state's own website carries it.