The Oroville dam may fail, and here is the
reason why. The top layer of rock is "rotten,"
and will be quickly eroded and washed away if
water tops the emergency spillway again. The dam
could be breached to about 100 feet down,
releasing a flood of catastrophic proportions.
People who have returned to the town of Oroville
are also reporting that workers are not allowed
to speak to the public.
LOS ANGELES, CA - There is a reason why
the evacuation order for Oroville and
elsewhere has not been lifted. The odds of
the Oroville dam failing are likely much
higher than what is being discussed between
authorities and the public.
One Monday, it was predicted the
evacuation order would be lifted as water
levels dipped below the level of the
emergency spillway and a dry spell
approached. Yet despite a few solid days
without rain, the evacuation order has not
been lifted. People have not been allowed to
return to retrieve pets, keepsakes or other
important possessions. Many people still
have just what was in their pockets in
There is a major issue with the dam. The
top 100 feet of rock is considered "rotten."
This means it is fractured and shattered by
natural forces. When it meets with the force
of water, it can break apart. The fractured
rock has been blatantly exposed by the water
flowing over the emergency spillway. That
water, which did not have a smooth flow over
the spillway, tore apart the uneven ground
and removed chunks of earth and rock. A
gash, estimated to be about 40 feet deep,
was quickly carved in the rock within just a
may undermine the Oroville dam.
If water tops the spillway again, it will
widen the gash. If it widens it enough, the
top 100 feet of the dam in front of the
emergency spillway will fail, and a
significant portion of water from Oroville
reservoir will cascade into the Feather
River and fan out in the valley below. The
town of Oroville will be the first
A close up of the damage caused by the
erosion in front of the emergency spillway.
If more water crests the spillway, the dam
could fail entirely.
There is also evidence water is
percolating into the rock under the
spillway. Bubbles are visible in the water
behind the emergency spillway. The bubbles
are large, frequent and visible from the
Now for the grim calculus.
Officials have wanted to drain the dam by
50 feet before new rains begin on Wednesday.
The water crests the dam at 902 feet. Since
Sunday's crest, the water level has only
fallen by 14 feet to 888 feet. In the next
24 hours, the water level may drop another
15 feet, give or take. The water will be
about 20-25 feet above the goal set by
engineers for safety.
The fracture in the earth reveals the
shattered nature of the 'rotten' rock below.
This is the source of the problems for the
dam, along with the fact water cannot flow
smoothly over the emergency spillway to the
Feather River below.
The only variable now is the rain. How
much will the area get? How much runoff will
enter the reservoir in the coming days? This
is difficult to predict, but the reservoir
is intentionally designed to capture as much
water as possible from the surrounding
While the surrounding area will receive
at least three to five inches of rain, those
few inches end up as several feet of water
in the reservoir. Needless to say, the math
is close enough that authorities have
refused to lift the evacuation order at all.
A view from
above the spillway towards Oroville in the
Despite the order, which applies to
nearly 200,000 people, some residents have
sneaked back into Oroville. These residents
have initiated rumors, which remain
unconfirmed, that they attempted to speak to
workers. Workers have privately expressed
serious concerns, but have admonished they
are not allowed to speak to the public. We
cannot give these rumors any credence as we
have no way of fact checking that such
conversations have taken place. However, if
such rumors are true the suggests that
authorities are very pessimistic about their
chances for saving the dam.
If Oroville dam fails, it will be one of
the largest engineering disasters in
American history. It will be on par with
Chernobyl and Fukushima, although the
long-term consequences will not be as
People thinking about returning to
evacuation zones should think twice. The
most likely time of failure for the
structure will be around Friday, when the
greatest rains will impact the area.