KEENE, N.H. (MyKeeneNow) City officials and conservation partners are preparing for a potential surge in amphibian activity Tuesday night, but are asking residents to avoid visiting migration sites due to forecasted thunderstorms.

The weather conditions — warm temperatures combined with rain — could trigger what naturalists call a “Big Night,” when large numbers of frogs and salamanders emerge after dark to travel to breeding wetlands. While the phenomenon draws curious onlookers each spring, safety concerns tied to lightning and thunder have led organizers to discourage visitors from heading out.

The Harris Center for Conservation Education said its naturalists will not be stationed at local crossing sites if storms develop, and the public is being asked to wait for a safer evening to observe the migration.

Despite the warning, the City of Keene plans to move forward with temporary road closures aimed at protecting migrating amphibians. North Lincoln Street will be closed to all traffic, while Jordan Road will be shut down to through traffic from about 7 p.m. Tuesday through 7 a.m. Wednesday.

The closures are designed to reduce vehicle-related deaths among amphibians as they cross roadways — a significant risk during migration events. Volunteers have helped thousands of animals safely reach breeding areas over the years, but officials say road closures provide broader protection.

Keene has been a statewide leader in amphibian conservation, becoming the first community in New Hampshire to implement migration-night road closures. The effort expanded in recent years to include multiple crossing sites, supported by data collected through volunteer “Salamander Crossing Brigade” programs.

Officials say migration nights are highly dependent on weather and typically occur on the first warm, rainy evenings of spring, anytime between March and early May.

While families are often encouraged to observe the crossings under normal conditions, organizers emphasized that tonight’s storms make it unsafe to be outdoors.

Residents can monitor future migration forecasts and road closure updates through the Harris Center’s website.