For two consecutive days, semi-trucks have crashed on I-80 in California. 

California Highway Patrol and Caltrans shared photos of the crashes. 

CHP says drivers in the Donner crashes suffered only minor injuries. There's no immediate word on the conditions of the other drivers. 

CHP reported a few more crashes during the night along I-80. 

CHP says drivers are urged to be prepared and need to plan ahead if traveling through the mountains. Remember to allow more travel time, reduce your speed, increase your following distance with the vehicles in front of you, and turn on your vehicle’s headlights if your windshield wipers are on - it's the law in California. 

As for Nevada, NDOT offers these safety tips:

NDOT rainy driving tips