Sciency Thoughts: Santa Barbara County

Showing posts with label Santa Barbara County. Show all posts

Tuesday, 9 January 2018

Landslides kill at least five in Santa Barbara County, California.

At least five people have died and a number of large number of homes have been damaged or destroyed in a series of landslides and flash floods in Santa Barbara and Los Angeles counties, California, on Tuesday 9 January 2018. All of the known deaths occurred in the Montecito and Carpinteria areas of Santa Barbara County, where a number of people, including several children have also reportedly been injured. Local authorities are so concerned by these events that evacuation orders have been put in place in parts of Los Angeles, Santa Barbara and Ventura counties.

A search dog enters a damaged building to look for survivors following a mudflow in Montecito, Santa Barbara County, on 9 January 2018. Santa Barbara County Fire Department.

The events occurred following a severe rain storm that brought over 12 cm of rain to many areas in the space of a few hours. Landslides are are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. In this case much if the rain fell in areas that had been badly affected by wildfires late in 2017. This made communities particularly vulnerable to landslips and mudflows, as the wildfires had destroyed much of the natural vegetation that covers hillsides in the area, the roots of which would normally help to stabilise the hillside during severe weather events.

A mudflow covering a road in Los Angeles County following a severe rainstorm on 9 January 2018. Los Angeles Police Department.

Sunday, 18 October 2015

Flash flooding brings chaos to South California.

Many areas of southern California are recovering after a series of thunderstorms caused flash flooding across parts of Los Angeles, San Luis Obispo, Santa Barbara, and Ventura counties on Thursday 15 and Friday 16 October 2015. The flooding triggered mudslides and landslips in many areas, blocking roads and trapping people in vehicles as well as causing damage to homes and other properties. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. No loss of Human life has been reported following the incident, but farms in many areas are reporting losses of Cattle and other livestock.

A pickup truck trapped by a mudslide on State Route 58 close to the Mojave Desert. CBS.

Flash floods are a common problem in southern California (and other areas with a dry climate) as protracted periods of dry weather can cause topsoil to dry out completely, making it vulnerable to being blown away by the wind. When rain does arrive it then falls on exposed bedrock, which is much less absorbent, triggering flash flooding as the water escapes over the surface of the ground rather than sinking into it. These floods wash away more topsoil, making the problem progressively worse over time. In Los Angeles this is reflected in the concrete channel which contains the Los Angeles River; a spectacular concrete structure which contains for much of the year only a tiny trickle of water, but which was built after a series of devastating floods in the early twentieth century.

Los Angeles River and flood control channel. US Army Corps of Engineers.

The floods come after several months of extreme drought in southern California, that has killed of plantlife in many normally non-arid areas, weakening the network of roots that tends to protect hillsides against collapse, and hardening the soil surface, making flash flooding more likely. It has been suggested by some observers that this may be the beginning of a much wetter climate phase associated with this years El Niño weather system over the southern Pacific Ocean, a phenomenon that typically brings high levels of rainfall to the southwest United States, though if this is the case then the weather has arrived dramatically early, as the increase in storm activity associated with El Niño does not usually begin in California till December.

Vehicle trapped in mud in Green Valley, California. KABC-TV/AP.

The El Niño is the warm phase of a long-term climatic oscillation affecting the southern Pacific, which can influence the climate around the world. The onset of El Niño conditions is marked by a sharp rise in temperature and pressure over the southern Indian Ocean, which then moves eastward over the southern Pacific. This pulls rainfall with it, leading to higher rainfall over the Pacific and lower rainfall over South Asia. This reduced rainfall during the already hot and dry summer leads to soaring temperatures in southern Asia, followed by a rise in rainfall that often causes flooding in the Americas and sometimes Africa. Worryingly climatic predictions for the next century suggest that global warming could lead to more frequent and severe El Niño conditions, extreme weather conditions a common occurrence.

Vehicles trapped by a mudslide on California Highway 58 in the Mojave Desert. Mark Ralston/AFP/Getty Images.

Hopes that the onset of high rainfall may bring an end to California's drought are also likely to be thwarted by the low state of reserves in the state's aquifers (underground water resources) which have been heavily over-exploited for industry and agriculture for some years. Such aquifers are slow to refill, with the effect that even a particularly long and wet Californian winter is unlikely to have much of an effect without a change to water-use policies in the state.

Sunday, 31 May 2015

Major pollution incident after oil pipeline ruptures in Santa Barbara County, California.

Clean-up crews are struggling to cope after a ruptured pipeline was discovered to have leaked around 2500 barrels (400 000 litres) of crude oil in Santa Barbara County, California, on Tuesday 19 May 2015. The pipeline, operated by Plains All American, was initially shut down after a mechanical problem was encountered at 10.45 am, then restarted at 10.55, before being shut down by a remote operator at 11.30 after a drop in pressure was detected. At 11.42 the Santa Barbara Fire Department received a call reporting a ‘pungent oil smell’ on Refugio Beach, leading to an investigation which at 12.20 pm led to firefighters discovering crude oil flowing from a culvert (storm drain) onto the beach.

Oil collected by volunteers from Refugio Beach on 21 May 2015. Jae Hong/AP.

The Santa Barbara Fire Department notified Plains All American, who sent a response team that constructed a sand and rock barrier to block further oil from escaping from the culvert, and estimated that around 21 000 gallons of oil (500 barrels or 80 000 litres) had been released, an estimate which was later raised to 105 000 gallons (2500 barrels or 400 000 litres), of which around 20 000 gallons (480 barrels or 75 000 litres) of oil is thought to have entered the sea. At this time the Coast Guard, National Response Center and Environmental Protection Agency were notified, and several local beaches were closed to the public and fishing and shellfish harvesting banned in the local area.

The source of the May 2015 Santa Barbara oil spill, and the culvert through which it reached the beach. John Wiley/Wikipedia.

Shortly after the spill was discovered volunteer teams began a clean-up operation, though they struggled to cope due to the scale of the spill, and report that they were not joined by professional clean-up teams employed by Plains All American, or the county, state or federal government for ‘several days’. A week after the incident was reported it was estimated that less than 6% of the escaped oil had been recovered, and a large number of oiled Seabirds and Seals have reported, and where possible taken to recovery centres for treatment. Significant numbers of dead Fish and Invertebrates have also been reported, and concerns have been raised that the oil may present a threat to Whales, which migrate through the area at this time of year.

Volunteers clean an oiled Pelican at a center run by the UC-Davis led Oiled Wildlife Care Network. East County Magazine.

The Santa Barbara Channel was the scene of a major oil spill in 1969, in which 3.4-4.2 million gallons (81 000-100 000 barrels or 13 000 000-15 000 000 litres) of crude oil escaped from an oil well blowout which was not capped for 10 days. This incident led directly to the formation of a number of prominent US environmental protest groups, and a tightening of environmental restrictions in Santa Barbara County, where all pipelines are now supposed to be fitted with automatic cutouts (which detect drops in pressure within pipelines and shut off the supply of oil without human intervention). Since the introduction of these regulations only a single major incident has occurred, when in 1997 a platform operator manually overrode an automatic cutout on a pipeline connecting an oil well to the shore which had a faulty weld, leading to the spillage of 6800 gallons (160 barrels or 26 000 litres) of crude oil.

Volunteers cleaning oil from a Santa Barbara beach in 1969. The oil is being soaked up with straw, which is then placed in drums for removal. AP.

However it has been reported this week that Plains All American won exemption from regulation by Santa Barbara County in a court case in the 1990s and the affected pipeline was not fitted with an automatic cutout. This is of particular concern as the amount of oil lost from the pipeline, 2500 barrels, represents over an hour of pumping at the pipeline’s maximum capacity (2000 barrels per hour) and nearly two hours at the rate at which the pipeline was being operated (1300 barrels per hour), implying that even if 100% of the oil was being lost from the pipeline (unlikely) it still took two hours for Plains All American to detect the fault, and that if a lower percentage of oil was being lost the leak must have persisted for several hours.