Wind patterns this week are expected to continue to plague Big Island firefighters who are battling a large wildfire on the southern flank of Mauna Kea.

Army officials yesterday reported that the blaze is 70 percent contained. The blaze has burned 1,386 acres since it started a week ago.

Daytime winds of five to 15 mph, and light winds tonight are expected to continue through the week. Light slope-driven winds are expected to dominate the fire area through Thursday.

Army officials said ground crews continue working the south slopes of Mauna Kea. At the area along Saddle Road, fire engines are conducting mop up and patrol operations.

Two helicopters were used yesterday for water bucket drops.

No structures have been burned.

Police arrested and charged the suspected arsonist, 31-year-old Christopher Pratt.

The fire began 9:30 a.m. Aug. 22 about a quarter-mile east of PTA’s main gate near Mauna Kea State Park.

Saddle Road remains open with detours in place at mile marker 29 and 34.5, officials said.