Why did the California mudslides happen?

California is known around the world as a kind of paradise. But its beauty has been recently scarred by natural disasters. For the final months of 2017, wildfires blazed throughout several parts of the state, including around Los Angeles. When these fires were finally put out last week, Californians hoped that the new year would be kinder to them.

But so far, 2018 hasn't offered much relief. Early last Tuesday morning, the L.A. neighbourhood of Montecito was devastated by a new natural calamity.

Powerful mudslides.

Embed from Getty Images

The mudslides have covered neighbourhoods in rivers of mud, trees, poles, rocks, and, in some cases, massive boulders. And not only have the mudslides come right after the fires, they were likely caused by them, too.

When the solution starts a new problem

How exactly? Let's backtrack a bit.

Embed from Getty Images

One of the biggest factors behind the fires in California was a lack of rain. When rains finally did come earlier this month, they meant an end to the fires that had burned for weeks. However, too much rain — which is what California got — led to a brand new problem. The mudslides.

Normally, heavy rain is absorbed by soil and vegetation. The water sinks into the ground, where it is drunk up by the roots of millions of thirsty trees. (The roots also help hold the soil together even if the rain is extremely heavy). But after strong wildfires, the soil becomes hard, dry, and covered in debris from burned trees—making it way less absorbent than normal soil. And the weakened trees' roots do a much poorer job of holding the soil together.

Embed from Getty Images

The result? Water rushing over the surface of the soil, sliding down hills, and carrying with it mud and ash from the fires. The heavy rainfall that triggered the Montecito mudslides only lasted about three hours or so. But they were enough to cause major damage. That's because the hills above Montecito were so parched by the fire, the soil collapsed and was washed into the neighbourhoods below.

Staying on guard

Embed from Getty Images

Rescue workers are doing their best to help those who have lost homes and to repair damage. However, getting to damaged areas is more difficult as roads and neighbourhoods are clogged by debris. Large parts of Montecito have been evacuated and major highways shut down.

California's government is also likely to begin working on plans to help protect other vulnerable areas from future mudslides. Experts warn that what happened in Montecito could still happen in many of the places hit by wildfires.