A race against the weather to avoid disaster at California’s Oroville Dam

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disaster at California's Oroville Dam
Mandatory evacuation orders remain in place for Butte, Sutter and Yuba counties Tuesday.
Authorities are scrambling to drain the swelling Lake Oroville and repair damages to a critical flood control measure ahead of a storm expected later this week.
Residents were ordered to leave the area Sunday after massive damage to an emergency spillway — which lets excess water out when Lake Oroville’s level rises to overflow the dam. If the spillway fails, it could flood communities downstream with what authorities warned could be a 30-foot “wall of water.”
 
As repairs are underway, evacuees have gone to shelters, pitched tents in parking lots and found makeshift arrangements for what could stretch for days.
Water gushes over the primary spillway at Oroville Dam in Northern California. At least 188,000 people have been evacuated from nearby counties in recent days after erosion caused damage to two spillways and, combined with recent heavy rains, sparked fears of possible flooding.
He said he requested federal response aid.
Chunks of concrete are seen breaking off in the dam's primary spillway on Tuesday, February 7. Lake Oroville managers stopped sending water over the spillway Tuesday after noticing the damage caused by erosion.
The main spillway, which is lined in the oroville dam failure inundation map, or paved, has a hole almost the size of a football field and at least 40 feet deep to form in the lower part of the channel. It can’t be fixed immediately and needs to be used through March, which marks the end of the rainy season.
It’s being used to drain the lake at a rate of 100,000 cubic feet per second in an effort to reduce the water level. Normal flows down the main spillway are about 55,000 cubic feet per second.
The emergency spillway, which is an embankment covered with trees, is a last resort and was used for the first time in its 48-year history on Saturday. Lake water began washing into it this weekend and prompted the evacuation order when officials noticed damage on the spillway.
The lake water flows into the emergency spillway when it reaches 901 feet. As of Monday 6 p.m., the water levels decreased to 894 feet.
Via:  CNN