Travel Reference
In-Depth Information
During the 1920s, someone jammed logs into Handkerchief Pool, effectively killing it.
Some years later sufficient trash was removed from the pool to partially restore its activity, but
it's now filled with sinter. Thick beds of cyanobacteria usually surround it. Occasionally in re-
cent years, it's come back to life as a small geyser.
Rainbow Pool
and
Sunset Lake
are brightly colored big pools at the boardwalk's end. Both
of these have acted as geysers but have not erupted in the past several years. Sunset in partic-
ular sometimes boils up a few feet at its center, creating large steam clouds. When conditions
are right and Sunset Lake is at its hottest, you'll see impressive concentric waves and reflec-
tions of color in the steam. As with all these hot springs, the colors around the periphery come
from mats formed of Archaea, bacteria, and algae.
A separate stretch of boardwalk to the south takes you to
Emerald Pool.
This is one of the
most famous pools in Yellowstone and is a truly unusual deep emerald green at its center with
orange around the edges. The bacteria can grow inside this pool due to its relatively cool tem-
perature (around 150°F/66°C). But watch out! It's
not
cool enough to touch!
Emerald Pool's green is a combination of blue water and yellow bacteria.
A trail you might want to take from here joins the main walkways around Upper Geyser
Basin in just under a mile (1.5 km). Park in the Black Sand Basin parking lot and cross the
Grand Loop Road (carefully!) opposite the parking lot entrance. The first thermal feature on
this former main road segment is Black Sand Pool in about 0.3 mile (0.5 km). Features on this
trail are described from its Daisy Geyser end on
pages 102-3.
Continuing on the Grand Loop Road 15.8/1.2
Old Faithful interchange. Built in 1969, this
urban-type interchange has been called a “disorienting concrete merry-go-round, the park's
most intrusive feature” by Eric J. Sandeen of the University of Wyoming.
Take the ramp to the right for Old Faithful Village and Upper Geyser Basin. Continue
straight for West Thumb Junction.
