From the Washington State Department of Transportation:
I-5 is closed in both directions in Skagit County south of Burlington. Traffic is being diverted off southbound I-5 at Exit 230.
On southbound I-5 at Chuckanut (exit 231), a signed detour will take traffic west on SR 20, south on Best Road, east on Fir Island Road and back to the freeway at SR 534.
Southbound I-5 is closed at George Hopper Road. A detour will take traffic east on George Hopper, south on Riverside Drive and west on SR 528 back to the freeway.
Northbound I-5 has a signed detour directing traffic off at SR 534, then west on Fir Island Road, north on Best Road and east on SR 20 back to I-5. There will be no lanes closed at SR 534.
Northbound I-5 is closed at SR 538 and traffic is detoured east on SR 538, north on Riverside Drive, west on George Hopper Road and back to I-5.
For an alternate route, take eastbound SR 20, then south on S. Burlington Blvd. and west on E. College Way (SR 538) to southbound I-5.
Northbound I-5 traffic must exit at Exit 227. An alternate route is east to E. College Way to northbound Riverside Drive-S. Burlington Boulevard, then west on George Hopper Road to I-5.
To use SR 9 as an alternate northbound route, bypassing Mount Vernon, take Exit 221 at SR 534 east to northbound SR 9 to SR 20 westbound to I-5.