Breaking tonight, the state of emergency here in California as heavy rains bring catastrophic flooding to millions, tens of millions under flood alerts across the west as a powerful storm triggers flash floods and evacuations here in Los Angeles.

Heavy rains turning hills into mudslides, life-threatening floodwaters, washing out homes and first responders rushing to save people trapped inside their cars.

This new storm set to bring heavy snow to the East Coast right after Christmas. We are tracking all of it.

In the search for answers after a terrifying nursing home explosion in Pennsylvania, rescuers pulling dozens to safety and desperate family members, finally reaching loved ones the big question tonight why did it happen and just in tonight the justice department saying there may be a lot more emceein files in previously thought tens of thousands of documents and images already released but tonight there may be more than a million more on the way.

The little drummer boys and girls are back for Christmas Eve in Bethlehem after years of bloodshed in nearby Gaza,

the moving message from the first American Pope as he celebrates his first Christmas Eve Mass.

Then their parents had to push to get these boys the same life-changing gene therapy,

but now they finally got it just in time for the holidays. And there is good news tonight about the

heartwarming bond between a boy and man's best friend and how they found it when they needed it the

most. This is NBC Nightly News with Tom Yamas.

Good evening from alongside a raging Los Angeles River.

I'm Gotti Schwartz in for Tom, and right now we are just behind our studios, and this is what

the L.A. River looks like in the middle of an atmospheric river.

Usually it's just a trickle, but you can see it is a

torrent of water. Meanwhile, up in the hillsides, inches of rain have turned into mudslides impacting so

many homes. Hundreds of people right now under evacuation orders. Meanwhile, rescue crews have been

braving the elements trying to get to stranded drivers.

Our Dana Griffith starts us off in this California state of emergency headed into Christmas Eve.

Tonight, torrential rain is drenching the West in snarling traffic for people still trying to get

out. An area in San Bernardino urging residents to shelter

in place as heavy mud flow and debris inundate the community. Water rescues being reported

across the region. Streets like this one completely off limits after being overcome by raging water.

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