first time in eight years
YELLOWSTONE NATIONAL
PARK, Wyo. (AP) A
large geyser that hadn’t erupted
since 1998 surprised two
hikers near the edge of Norris
Geyser Basin with a roar and
burst of steam.
Lee Whittlesey and Betsy
Watry heard the Ledge geyser
before they saw it. “It was like
a jet plane,” Whittlesey said.
The geyser erupted at full
bore around 5 p.m. Saturday,
sending a plume of steam
about 100 feet high.
“I’ve been in the park 30
years, and this was the first
time I’d seen Ledge erupt,”
said Whittlesey, who is
Yellowstone's historian. “Now
I can check that one off.”
Watry, who works for the
Yellowstone Association, said
they were shocked at the show
that unfolded about a quartermile
away.
“We just stood there
stunned and watched it for a
while,” she said.
The eruption coincided with
other unusual activity at
Norris over the weekend,
including the eruption of other
sporadic geysers and changes
in surface water. Henry
Heasler, Yellowstone’s lead
geologist, said Norris
appeared to be undergoing a
“thermal disturbance” an
infrequent and often sudden
shift in activity.
A smaller disturbance
occurred in February. There
were no disturbances last
year.
Such disturbances result
from subsurface activity that
brings water closer to the surface.
“Imagine if there was a big
kind of geyser burp under
most of Norris,” Heasler said.
Among other changes, the
usually quiet Vixen geyser has
been erupting, Pearl geyser's
water has changed from clear
to opalescent, and water elsewhere
in the basin has turned
murky.
The duration of such disturbances
is difficult to predict.
Heasler compared the phenomenon
to the ringing of a
bell. “Some bells quiet down
very quickly, and others can
ring for a long time,” he said.
Scott Bryan, author of “The
Geysers of Yellowstone,” said
Ledge was active in the early
1970s until a thermal disturbance
in 1974. After that, eruptions
were less frequent until
1979, when it quieted down
completely.
The geyser came back to
life in 1993, with eruptions
roughly every nine to 14 days,
and fell silent again in 1998.
