USA Trip Week 4

Lassen Volcanic Area. Mrs Lockwood stood beside the lava flow from the base of Cinder Cone

which erupted in the 1600's. The lava was a slow moving mass which cooled to form the large dark rocks in the photograph. Below is Cinder Cone itself which formed at the same time but was formed by ash and small rocks being blown into the air next to the vent forming a perfect cone.

This is a Cone Volcano.

The path to the summit was steep and strenuous to climb up but Mrs Lockwood made it and stood on the top by the crater rim.

This is Lassen Peak (3187m,10457ft) which is a Plug Dome Volcano. It is the 2nd largest Plug Dome Volcano in the world and is still "active". There had been a lot of snow in this area 45cm above 6000ft altitude. This peak last erupted in a series of explosions between 1914 and 1915 with the last most dramatic eruption in May 1915. The area just off centre right is known as the devastated area and is approximately 2.5 miles across and descends over 5 miles from the summit. This area is where the hot gas cloud (Pyroclastic Flow) and then the melted snow , hot lava rocks and ash ejected during the explosions formed a raging torrent of mud that flowed down the mountain wiping everything in its path. (Lahar).

Lassen Volcanic Park is the largest hydrothermal area west of Yellowstone. The area is one of the few areas in the world that has all 4 types of volcano within the park area. Composite, Shield, Plug Dome and Cinder Cone.
This lake is a just below Lassen Peak on the opposite side to the devastated area and is a tranquil spot. In contrast to the hydrothermal areas of Devils Kitchen which is a mass of steaming fumaroles, boiling water and mudpots.

Mrs Lockwood sat by Terminal Geyser which is close to Boiling Spring Lake. The water in the lake is warm at 120F. Hydrothermal areas are very dangerous to walk in and access is often prohibited except on official trails as the earths crust is thin and people have been known to break through and fall into boiling water and mud which is often very acidic causing severe burns.

Prior to Lassen Volcanic Area we were at Lake Tahoe. When we travelled to Lake Tahoe from San Francisco we were caught in an early winter storm on October 5th. It snowed very heavily and many roads were temporarily closed. At Lake Tahoe which is a famous ski resort (Heavenly) in the winter they expect to get 6 metres of snow annually.


Lake Tahoe is the second deepest lake in the USA
at over 500 metres (1650ft). It is renowned for its clear water which is measured by how deep you can see a white disc in the water. It is still clear at least 20metres down.

It is a very popular year round resort with skiing in the winter and sailing and watersports in the summer. Hiking is done year round in the resort but you have to wear snow shoes in the winter.
The snow often comes very heavily in November and last year it lasted till July before all the roads were open.

The Lake has only one island within it but it has many sandy beaches. The snow melted very quickly when the sun came out.

This old paddle steamer sails daily around the lake for tourists.

The cold weather started the freshwater Kokanee
salmon spawning. This process starts in Taylor Creek where hundreds of salmon swim up the shallow river to lay their eggs in the gravel.

The female salmon die 2 days after spawning and become food for many other animals. The males become more brighly coloured and their shape changes with a hook nose. We saw several groups like the picture to the right with hundreds of salmon and they were very colourful.

This whole area has many historic as well as scenic trails. Although the Washoe Indians have lived for thousands of years in this area the first european explorers first discovered Lake Tahoe in 1846. We walked part of the overland Pony Express trail which ran across very wild terrain.