Flume Gorge

The Flume


Useful Information

Location: at the base of Mount Liberty.
Open: 12-MAY to JUN daily 8:30-17.
JUL to 04-SEP daily 8:30-17:30.
05-SEP to 21-OCT daily 8:30-17.
Open hours weather depending.
[2019]
Fee: Adults USD 16, Children (6-12) USD 14, Children (0-5) free.
[2019]
Classification: ExplainGorge
Light: n/a
Dimension: L=244m, W=6m, H=28m.
Guided tours: n/a
Photography: allowed
Accessibility: Not accessible, wooden staircases.
Bibliography:  
Address: Franconia Notch State Park, 9 Franconia Notch Parkway, Franconia, NH 03580, Tel: +1-603-823-8800, Fax: +1-603-823-8088
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.

History

1808 discovered accidentally by 93-year-old “Aunt” Jess Guernsey while fishing.
1883 a heavy rainstorm swept the hanging boulder from its place.

Description

Flume Gorge or The Flume is a strange geologic site, and while it is listed as a gorge and has a river running through, it is actually a really special gorge. It is a straight cleft which is 244m long, up to 6m wide, and up to 28m deep. The strange thing is that it is almost straight, not meandering like a normal gorge.

The rocks of the gorge are granite, a volcanic intrusion named Conway granite, which was formed 200 million years ago during the Jurassic. The magma cooled very slowly because it was stuck in a mushroom like form deep below the surface and isolated by the surrounding rock, and the result is granite. Erosion of the surface continued, and when another intrusion of magma occurred, it forced its path through cracks in the granite. As those cracks were rather narrow, with cold granite on both sides, the magma cooled much faster and formed a vertical sheet of basalt. Those basalt filled planar structures in the rock are called dikes by the geologists. Erosion of the surface continued and the granite was exposed, with its basaltic dikes. As the dikes are much less resistant to weathering than the hard granite, they were eroded and form those exceptional straight gorges. The walls consist of granite, but on the floor of the gorge you many see remnants of the main basalt dike, a black and fine-grained rock

The whole area was covered by an ice shield which was up to one mile (1.6km) thick, during the last cold phase. The glacier brought rocks from north in its slow flow to the south. It also planed the underground, but the granite was very resistant and not greatly changed. Some 8,000 years ago the cold phase ended and the climate became warmer, the current warm phase started. The melting ice produced enormous rivers of melting water which created impressive erosional forms and most likely the current state of the gorge was formed by such a river. Only the erosional forms and the huge blocks the ice carried are left from the glaciers. Those rocks or boulders are called glacial erratics, because they are often rocks from a completely different part of the continent, and they are so big and heavy (up to 300 tons) that no geologist could explain how they were transported to this spot. There are numerous such erratics in the area of the Flume, the most spectacular was a hanging boulder in the middle of the gorge. It was egg-shaped and 3.6m by 3m big. But it was washed away by the great storm of 1883, which also created Avalanche Falls at the top of the Flume by depositing huge rocks to form a 14m high waterfall.

Flume Gorge is part of Franconia Notch State Park, which was named after Franconia Notch, a mountain pass between the high peaks of the Kinsman and Franconia mountain ranges. It is traversed by a parkway, the I-93 or Styles Bridges Highway connects New Hampshire with St. Johnsbury. The park extends from the Flume Gorge at the south to Echo Lake at the north.

There is a huge parking lot and the Visitor Center at the highway. From here you can make the short walk into the gorge and back. This trail is developed with wooden walkways and staircases. Then there is a long trail, which is more than 3km long and includes a covered bridge from 1886, a granite outcrop named Table Rock, a small tectonic cave named Wolf Den which can ony be visited by crawling, and lots of glacial erratics.