From fire to floods. What knowledge can we draw from the terrible floods unfolding in California?

From fire to floods. From a series of vast wildfires in recent years, 2023 starts off with heavy rain and flooding in California.

We at 7Analytics watch the emergency unfold to learn and collect info that can help us prepare for similar events in the future.?

Here are some facts:

• Large parts of Southern, Central Coast and Northern California affected
• Nearly all of California has seen much above average rainfall totals over the past several weeks, with totals 400-600% above average values.
• San Fransisco’s New Year’s eve was incredibly wet - 13.9 cm (5.46 in) of rain
• 34 million Californians are under a flood watch – that is about 90% of the state’s population
• 200,000 homes, businesses and other power customers have lost electricity

New weather systems keep hitting the state after days of rainfall and already now 18 people have lost their lives.

Sunny state prone to flooding

California is no stranger to floods. It has 38 major rivers and river floods are by far the most common event type. All 58 counties of the state have experienced at least one significant flooding in the past 25 years, which resulted in loss of life and billions of dollars in damages.

However, the current rains are of an extreme nature. Nearly 33 cm (13 in) hit the San Marcos Pass in the mountains off Santa Barbara in one go. “As far as we know, this is a historical record for the amount of rain in that location,” said Eric Boldt of the National Weather Service, said at a news conference.

In response, President Biden declared a state of emergency for California on Monday enabling?assistance from the Federal Emergency Management Agency.

Connected risks

With the heavy rains the risk for mudslides goes up. This is the case in Montecito which was hit by a mudslides that killed 23 persons in 2018.

This time around the citizens were evacuated at first only to be allowed to return to their homes recently.

The region is particularly dangerous due to the steep topography (from sea to almost 1,500 m/5,000 ft) and two types of rock that make up the mountain - shale and sandstone which erode easily.

Do we know the risk?

Given the natural hazards of California the state′s department for water resources put forward that all Californians should know their flood risk and be prepared. They guide citizens to MyHazards, an online service provided by the Governor’s Office of Emergency Services, where address specific flood risk can be found.

All Californians should know their flood risk and be prepared

Such sources are often the best risk info a hand, but are they adequate??

Recent media coverage says plainly: no! In December 2022, the Washington Post claimed that government flood-risk and insurance maps often leave residents unprepared for the threats.

In many recent flood cases, the high-risk locations identified by the US Federal Emergency Management Agency’s (FEMA) flood maps did not cover the actual events. The claim is that FEMA’s maps fail to warn Americans about flood risk.??

What do we draw from these catastrophic events?

Above all, we see a need for higher quality knowledge on nature risk enabling everyone to understand nature and prepare for events like the one taking place in California.

While river floods are extremely impactful, focus must be maintained on difficult-to-predict flash floods and - not the least - the interlinks between huge amounts of water and other nature risks. In California, predicting how water affects soil stability and the risk of mud slides may safe lives. Similarly, the impact of strong winds alter the risk patterns.

We, the 7Analytics team, work hard to increase precision and ability to predict flooding as well as linked risks such as mud and landslides. We find that much better knowledge is crucial in adapting to a more extreme future. Read more here.