An ‘atmospheric river’ will dump rain on SoCal. What? 

A major storm caused by a phenomenon called an atmospheric river is heading to Southern California and leading to evacuation orders in some areas

Several hour period of some consistent rainfall and heavy at times. That storm is expected to bring significant rainfall to Southern California and could cause even more significant issues

The system will likely bring the heaviest rainfall to SoCal this year

It's that atmospheric river, it's that extra moisture that's coming in that's going to make this like a really, it's going to be a really big rain event

I mean, Southern California hasn't had a storm like this, I mean, since probably the beginning of the year

What exactly is an atmospheric river? Out in the Pacific Ocean, I mean, there's still weather happening out there, right

Cold air, hot air. So you'll still get moisture that kind of bubbles up to the surface

And then what happens is, is the westerly winds, right? So that's why when you fly from the West Coast to the East Coast, it's faster than the East to the West, right

The westerly winds come in and they drag that air. They drag the air and the moisture

It's basically just a movement of air pushing along moisture. Evacuation orders went into effect in several parts of SoCal, including many parts of Los Angeles

The massive L fires earlier this year are now calls for concern because of this pending storm Those fires loosen up the terrain which can cause issues during a major rainfall

Mudslides, you know, obviously, especially in the L.A. area, you've got a lot of hillsides that can come down really quickly

Cliffs, I mean, you know, all the way up and down the coast. People really do need to heed those warnings because they're trying to save your life

So if you hear about something, if it pops on the TV or, you know, just stay vigilant over the next few days

And that's not the only concern from the fires and rain combination. Who knows what toxic crap is just sitting on those lots

I mean, I know they cleaned a lot of them, but I don't think they've gotten all of them

There could be some really dangerous, toxic runoff, like coming from the Palisades, coming from Altadena

The rain is expected to stick around throughout the weekend. From what I've read this afternoon is probably like late Friday, probably until like all day Saturday, probably a little bit of Sunday

And then it looks like there's another system. We'll get like a break Monday, Tuesday, then another one from the middle of next week

So really, really going to be a rainy, you know, 10 days or so for Southern California

One positive experts pointed to is that this rain will likely mark the end of fire season in SoCal

For Straight Arrow News, I'm Lauren Keenan. If you want more on this story, download the Straight Arrow News app or visit san.com