While it may seem like winter's grip on NH and VT is over, please keep in mind these important factors to still consider when planning travel in the backcountry!
Melting snow pack, especially in good snow years (like this one, yay!) can cause sudden and unexpected flooding, even where traditional river beds might not seem troubling. Plan your trip with alternate routes, and be prepared to turn back if you meet a raging, flooded river. DO NOT expect to be able to ford flooding rivers especially with cold water. When boating, be aware of sudden changes in water level, and also strainers, as winter storm damage may leave rivers denuded and filled with downed trees.
Even warm spring days cannot bring water temperatures up to a safe temperature. Any activity near water must take into account the frigid temperatures of recently melted ice and snow in the rivers. Swimming and boating without wet/dry suits should not be attempted, even with PFDs, until water temperatures are above 52 degrees F. See also: for more info].
Winter is far from over in the northcountry in what we traditionally call "spring". The no-frost day typically used by local farmers is JUNE 1st! Which means there could be snow any time of the year except high summer, and in the White Mountains of NH, there can be snow any time of year. Worse than snow is cold rain - at 35 degrees F, a rainstorm could mean serious trouble for the unprepared. Cold temperatures and wet weather are high risk factors for Hypothermia. Always bring rain gear and plan ahead for wet weather.
Deep Snow Packs
It is possible to have deep snow pack in the mountains well into the spring. If you do not have appropriate footwear and expertise, you may not be able to travel to your intended destination or use the trails you planned to use. You should prepare adequately for winter conditions until late May or early June in the high summits and monitor forecasts. Be prepared to turn back or take alternate routes.