It’s official: Mud season is here and it may be the earliest ever

  • Ryan Calsbeek, left, and Brittny Calsbeek, both of Hanover, N.H., ride their horses, Hank and Peanut, up Baker Hill Road in Lyme, N.H., on Saturday, March 19, 2022. Brittny Calsbeek joked that riding a horse is the only way to get around once mud season starts. (Valley News / Report For America - Alex Driehaus) Copyright Valley News. May not be reprinted or used online without permission. Send requests to Alex Driehaus

  • Highway crews lay down stone and gravel on Unity roads covered in mud. Spring thaws, such as this one shown in a past April, usually present challenges for maintaining roads. This year, however, those issues are developing earlier than normal with the unofficial arrival of mud season. AP file

Monitor staff
Published: 2/18/2023 8:50:09 AM

You’re not imagining it: Mud season has arrived and it’s early, maybe the earliest ever.

On Friday the state began posting weight limits on roads to keep heavy vehicles from damaging pavement as it thaws and buckles. The N.H. Department of Transportation makes this announcement every year but since 2005, when records became available, it has never been made this early in the season.

Only three previous times in the 16 years for which records exist has the announcement been made in late February rather than in March. The closest to this year’s date was in 2018 when the state road posting announcement came on Feb. 21, but usually it is made in the first or second week of March. In 2005, a late winter meant the announcement wasn’t made until March 31.

Alan Hanscom, state maintenance engineer for the DOT, said the state has “done some brief periods in January at times, but it did get colder and the signs came back down.” It takes an uninterrupted period of below-freezing temperatures to make highways become “solidly frozen” again, as required by regulations, and with Concord daytime temperatures slated to be in the 40s or 50s in the coming week and the March forecast calling for average temperatures, that seems unlikely to happen this year.

An early mud season is, like canceled outdoor winter sporting events and shortage of snow cover, the latest effect of this unseasonably warm winter.

Except for the brutally cold weekend of Feb. 3-5, temperatures have consistently been at or above long-term averages throughout New England since before Christmas. Seven Northeast states had the warmest January on record.

Warmer weather means sections of roads are vulnerable to breaking up as frost melts from under the road base.

Water, almost uniquely among all compounds, expands rather than shrinks when it freezes. When temperatures in late winter or early spring vacillate between freezing and thawing, water that has seeped underneath roads grows in the cold, pushing up pavement, then shrinks when it’s warm, leaving gaps where more liquid water can enter.

As this process repeats itself the road becomes weaker and more likely to break up when vehicles drive over it. Heavier vehicle are more likely to cause the damage; hence the need for weight limits at this time of year.

Weight limits can also limit damage to unpaved roads, surfaced with loose gravel or dirt.

Road postings are determined by local DOT district engineers. Many cities and towns make similar postings on their own roads as determined by their own road crews.

The maximum allowable vehicular weight posted sections of state highways is 30,000 pounds gross weight or the cumulative width in inches of all tires contacting the road surface multiplied by 300, whichever is less.

Under state law (Section 236:3-a), trucks carrying home heating oil, processed milk products or maple sap and septic pumper trucks are exempted from seasonal bans, as long as they get the approval of local district engineers.

Affected roads can be found on the Web at the top banner “Trucking-New Hampshire-Seasonal Posting.”

David Brooks bio photo

David Brooks is a reporter and the writer of the sci/tech column Granite Geek and blog, as well as moderator of Science Cafe Concord events. After obtaining a bachelor’s degree in mathematics he became a newspaperman, working in Virginia and Tennessee before spending 28 years at the Nashua Telegraph . He joined the Monitor in 2015.

Stay informed with our free email updates
Concord Monitor Daily Headlines
Concord Monitor Breaking News
Concord Monitor Dining & Entertainment
Concord Monitor Report For America Education
Concord Monitor Report For America Health
Concord Monitor Real Estate
Concord Monitor Sports
Concord Monitor Suncook Valley
Concord Monitor Contests & Promotions
Concord Monitor Weekly Most Popular
Concord Monitor Granite Geek
Concord Monitor Monitor Marquee
Concord Monitor Hopkinton
Concord Monitor Politics
Concord Monitor MY CONCORD
Concord Monitor Franklin


Support Local Journalism

Subscribe to the Concord Monitor, recently named the best paper of its size in New England.

Concord Monitor Office

1 Monitor Drive
Concord,NH 03301


© 2021 Concord Monitor
Terms & Conditions - Privacy Policy

Customer Service

Social Media


View All Sections

Part of the Newspapers of New England Family