Summer Rain
July 19, 2015
Summer rains are common at Hubbard Brook. Although precipitation causes streams to rise, much of the water is evaporated or transpired back to the atmosphere, reducing risk of downstream flooding.
Tropical Storm Irene
August 28, 2011
Tropical Storm Irene, the remnant of Hurricane Irene, dropped more than 5 inches of rain on Hubbard Brook and the rest of New Hampshire and Vermont in late August of 2011. Although ranked only the 9th largest precipitation event at HB since monitoring began in 1956, this storm came on the heels of two other large rain events (August 14-16 and August 21-22), causing the soils to be saturated and poised for flooding. Water samples taken by Hubbard Brook Experimental Forest scientists show that by the time storm waters had rushed past the Plymouth gauging station on the main branch of the Pemigewasset River, just downstream from the Hubbard Brook, the flood had carried over 59 million tons of sediment, 23,000 lbs of phosphorus, and 82,000 lbs of aluminum. That is equivalent to 454 freight train cars filled to the top with sediment, 43,500 50-pound bags of 5-10-5 fertilizer, and 2.3 million empty 12-ounce aluminum soda cans in just one storm event.
Autumn Rain
September 29, 2015
Autumn precipitation is conveyed quickly through soils and into streams. Cooler temperatures and scenescent leaves reduce loss through evaporation and transpiration.
Autumn Snow
October, 2011
Autumn Snow, October 2011. Occasional early snow storms can be particularly damaging, particularly if they occur before the trees drop all of their leaves. A severe early snowstorm battered the northeastern U.S. in late October 2011, where the weight of heavy wet snow dropped branches and toppled trees throughout the region.
Winter Base Flow
February 2015
Winter is typically a time of relatively constant ‘base flow’ contributed largely from groundwater discharge. Incoming precipitation in the form of snow is stored in the snow pack, rather than generating streamflow.
Winter Rain on Snow
March 2011
New England winters are characterized by occasional rain-on-snow events. The warmer temperatures associated with these events combined with the incoming rain causes stream flows to rise sharply and cause localized flooding. The flooding can be made worse by ice jams.
Spring Rain on Melting Snow
April 2019
Snow melt typically results in high stream flow in the spring. A large rain-on-melting snow resulted in very high flows in mid April 2019.