A spokeswoman for Hawke's Bay Hospital said she was in a critical condition and had been transferred to Christchurch for further treatment.
In light of the crash and inclement weather, police advised motorists to drive to the conditions at all times and to modify their driving as the weather changed.
It was vital people regularly checked their vehicles for roadworthiness, especially the condition of their tyres. Worn tyres had much less contact with the road in wet conditions than fully treaded ones.
Senior Sergeant Clint Adamson said the only crash yesterday that was possibly weather related happened when a van rolled into a bank on Avery Rd at Eskdale, about 8am. The 25-year-old female driver was not seriously hurt.
There had been no serious crashes yesterday.
"In these conditions, it's good news," he said.