Wet Winter Chaos in California
The after effects of Northern California’s winter deluge
Over the last five years the State of California has been subject to extreme weather conditions. In 2015 at the peak of the state’s crippling, five-year dry-spell, almost half of California’s population lived in areas of what officials call “exceptional drought.” During the 2016/2017 winter season, however, heavy rains pummeled California, pulling most of the state out of drought. The effects of these rains are clearly visible from space.
On February 11, 2017, the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor, part of the Suomi NPP satellite, captured this fascinating look at California’s sediment-filled rivers draining into the Pacific Ocean.
With 3–5 meter resolution imagery collected by Planet’s Dove and RapidEye constellations, it’s easy to examine the effects in more detail. On the same day the Suomi NPP imagery was captured, February 11, 2017—A Dove cubesat collected this image of the San Francisco Bay:
From up close, you can see the delicate hydrodynamics at play as an enormous amount of sediment drains from the Sacramento—San Joaquin Delta into San Francisco Bay. Urban and agricultural runoff, debris, and over 2 million gallons of sewage have also drained into the bay during this series of storms. However unsavory, sediment and runoff is often expected as a byproduct of storms of this magnitude.
Oroville
One of the key events associated with the storms was the extensive damage to Oroville Dam’s emergency spillway. In February, a bloated Lake Oroville reached its capacity, forcing 4,200 cubic meters of water per second down the spillway.
In this before and after imagery, we can see diverted water eroding the surrounding hillside.
When we look at the larger area, and combine Dove imagery with USGS elevation data, we can see why an emergency evacuation order was issued to the Feather River Basin: essentially, all of Oroville’s residents live below the lake’s elevation and directly in the path of an uncontrolled water-release event.
188,000 people in the basin’s low lying population centers were evacuated.
San Jose
Further south in California’s 3rd largest city by population, our satellites have spotted a rare urban flooding event. Examine these before and after of images of San Jose captured from about 400–500 kilometers up:
Notice the brown sediment-filled water of Coyote Creek overtopping its banks, flooding parkland, industrial parks, and residential neighborhoods, prompting the evacuation of 14,000 residents. Assessors say the flooding caused $70 million in damage.
As rains fall, sediment flows, rivers flood, and rebuilding begins, our monitoring constellation will collect data to help governments, insurers, and first responders assess damage, map progress, monitor infrastructure, and prepare for the next wet winter.
