Travel Reference
In-Depth Information
Islands
The seven named islands in Yellowstone Lake are, from largest to smallest: Frank, Steven-
son, Dot, Peale, Molly (actually two islands named Sandy and Rocky), Carrington, and Pel-
ican Roost. Frank, Peale, and Molly were named by or for members of the 1871 and 1878
Hayden Expeditions.
Winter and the Lake
In winter, ice nearly 3 feet (1 m) deep covers much of the lake, except where shallow water
covers hot springs. The lake freezes over by early January, and the ice doesn't break up until
late May or early June. Rangers on ski patrol used to take a shortcut to the Thorofare in the
southeast by crossing the ice from Lake Ranger Station to Park Point on the east shore.
Science and the Lake Bottom
In recent years, scientists have explored some of the lake's bottom using a submersible ro-
bot called a Remotely Operated Vehicle (ROV). They've learned that Mary Bay at the lake's
north end, where temperatures up to 212°F (100°C) have been measured, is a major hydro-
thermal explosion crater complex that erupted about 13,000 years ago. They've also found
deep pits that may be old explosion craters.
At least two other hot areas in the lake are being studied. West Thumb Bay is one of
these areas, with huge hot gas eruptions that stir up food for enterprising trout. Another is
east of Stevenson Island, where many active hydrothermal springs are found.
Spires as tall as 26 feet (8 m) grow in clusters on the lake bottom at one lake hot spot,
Bridge Bay. These pinnacles are made of the siliceous shells of diatoms, microscopic algae
that live and die near the lake bottom. Exactly how these hydrothermal features form is as
yet unknown.
Lava flows that are still very hot underlie much of the lake. Thus all the possible
thermal features that we see in the rest of the park are here, only modified by having a lake
sitting on them. The result is that many explosion craters dot the lake perimeter, and we
know from recent research that there are more on the lake floor. There are also domelike
features, some one-third of a mile (0.5 km) in diameter, bulging up perhaps due to steam.
An ongoing study called the Molecular All-Taxa Biodiversity Inventory is discovering
species previously not known to live in the lake, ranging from the smallest bacteria to crus-
taceans and insects.
14.1/6.5
Sand Point picnic area. The tables have no view of the beach,
but there's a shore access trail with a good view of long, narrow
Stevenson Island
and the
