Bad news for the water situation, but welcome news for potential visitors:
The main park road, Hwy 89 through Lassen Volcanic NP from north to south, is open to all traffic. It is recommended for vehicles 45' feet in length or shorter, and there are no alerts for snow on the road.
There are years when it does not reopen until late June or even early July, so this is exceptional. Keep praying for rain or snow, but if this is a year you hoped to see this beautiful park, take advantage of the opportunity.