PORTLAND, Ore. -- Saturday's snow storm caused wrecks on major roadways throughout the Willamette Valley, prompting the Oregon Department of Transportation to put a chain requirement into effect.

Chains are required on Interstate 5 from Wilsonville down to Eugene, as of Saturday night.

With snow turning to ice Sunday, roads are expected to get even more treacherous throughout the region. Multiple state agencies have asked people to stay home.

On Saturday, Oregon State Police reported multiple crashes on Interstate 5, particularly in the Salem and Albany regions.

In the Portland area, ODOT used salt for the first time on Highway 26 near Sylvan on Saturday. Spokesman Don Hamilton said they "saw improvements" after applying salt.

Drivers heading up the West Burnside hill are required to have chains or face a $160 fine from the Portland Bureau of Transportation.

Photos: Numerous crashes on area roads

TriMet has warned of potential delays and stoppages.

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In eastern Oregon, all state highways, including Interstate 84, were closed late Saturday afternoon in Union County.