UPDATE: 02/23/2015 11:31am New York State Police are saying that several vehicles were involved in an accident that occurred between mile markers 266 and 268 during what is being described as "a period of low visibility."

Authorities say that the westbound lanes are closed.  Traffic is still exiting at Exit 34/Canastota as vehicles involved in the accident are being towed from the roadway.

The eastbound lanes have been reopened.

UPDATE: 02/23/2015 9:34am The Department of Transportation says it is mandatory that all cars travelling between Syracuse and Canastota on the New York State Thruway exit at Exit 34 because of whiteout conditions.

Original Story:

An accident westbound on I-90 between Exit 34 and Exit 34A is blocking traffic in both directions for miles.

The New York State Department of Transportation is advising that all traffic must exit at Exit 34.

Severe weather conditions exist.

Drivers are advised to avoid the area if possible.