What's that cloud upriver? Eyewitness account of a lahar by USGS geologist Jeff Marso
View upstream below the footbridge
El Palmar, Guatemala on August 14, 1989
"While surveying the Nima II river near the town of El Palmar in
Guatemala, my colleague and I noticed a white steam cloud upriver. We
were working about 15 kilometers downstream from an active lava dome,
Santiaguito. A very heavy rainstorm was passing through that area and
the likelihood that a hot lahar was on the way was immediately
obvious.We scrambled out of the canyon as quickly as we could, gave our
equipment to our driver who exited with the vehicle at high speed, and
we raced for a nearby bridge with our cameras."
Footbridge Provides Safe View
"The cable suspension bridge was approximately 130 m long and
at its lowest point 10 m above deepest part of the river channel.
We made it over the channel just as the lahar rounded the bend upstream
from us. What began as a dull roar now approached a deafening
Front of lahar approaches bridge
brown splashing water and debris)
Here it Comes!
"As the lahar approached, rocks and mud splashed violently several
meters up and out of the channel. I clearly remember wondering if we
were high enough above the channel to be safe. I began taking photos as
soon as the front of the lahar appeared."
Lahar rushes downstream (from
There it Goes
"The lahar passed below us at what seemed an incredible speed and
with an overwhelming roar. The front of the flow was approximately 5
m high and filled the river channel. As the hot lahar became
larger, small rocks and mud splatter were thrown onto and over the
bridge. We decided that we were not high enough and ran for the safety
of the far bank. There, ground vibrations made it difficult to stand
and we had to shout to be heard over the roar. "
Santiaguito lava dome (note small
by Rain and Eruption
"The lahar we witnessed was the first of several that surged 60
km down the Nima II River for a period of 3 hours. We estimated
the lahar's speed at 50 km/hour. It was triggered by intense rainfall
that eroded newly emplaced rock debris from the Santiaguito Dome
complex perched in the crater of Santa Maria Volcano. Just 14 days
before, a portion of the dome had broken off and collapsed into the
headwaters of the Nima II River. This was the largest dome collapse
from Santiaguito since the 1930's and it provided plenty of loose
volcanic debris for water to erode away. "