Hey, from CNN. I'm Afoma DK.

With the five things you need to know for Wednesday, February 18th.

We start with a tragic update on nine missing backcountry skiers after an avalanche in California Tuesday morning.

The Nevada County Sheriff's Office says eight of them are dead and that they were buried by heavy snow near Lake Tahoe.

Sheriff Shannon Moon says one is still missing and presumed dead.

Please understand that this incident remains ongoing.

Our focus remains on recovering, but the snow and the unsure conditions are creating an issue to making sure that we can safely do that.

Moon says one of the skiers was a guide on the trip.

Six injured skiers were previously rescued, according to the sheriff's office.

All were on the final leg of their three-day backcountry trip in northern California,

Sierra Nevada Mountains when a wave of ice, rocks, and debris came crashing down.

A USDA forest supervisor says the avalanche spanned about the length of a football field.

When we come back, Mark Zuckerberg takes the hot seat.

Now to a historic trial on social media addiction.

For the first time, Met a CEO Mark Zuckerberg testified before a jury about claims that his platforms,

specifically Instagram, intentionally addict young people, and harm their mental health.

I spoke to CNN's Claire Duffy.

So Claire, how did Zuckerberg respond?

Right, Ifoma, Zuckerberg was essentially being asked whether his company prioritized profits over the safety of young users, including the now 20-year-old woman Kaylee who filed this lawsuit.

In his testimony, Zuckerberg said he believes he's handled keeping young users safe on Facebook and Instagram, quote, reasonably.

He was grilled on under 13 users accessing the platforms in violation of META's policies,

and on beauty filters that META's own experts said were harmful.

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