Washington State Patrol Trooper Guy Gill said the 44-year-old woman was out of her car helping other drivers that had spun out when she was struck and killed just after 5 a.m.
A trooper helping at the scene in the westbound lanes of the highway at Burnham Drive was also hit by another vehicle while outside of his patrol car. The trooper suffered a knee injury and was taken to a hospital to be checked out.
Several other people were injured in the multiple-vehicle crash, and officials said the westbound lanes of Highway 16 would be closed for several hours near the scene.
The name of the woman who was killed has not been released.
The crash was one of many collisions and spinouts that occurred throughout the Puget Sound area as drivers faced black ice on many roads and highways.
Officials urged drivers to be cautious, but with temperatures above freezing, ice on main roads should melt later in the morning.
Temperatures are expected to get to the low 40s today and we should see some sunshine before another wet and windy storm rolls into the area on Tuesday.
Power crews hope to use the break in the weather on Monday to restore service to many of the more than 55,000 homes and businesses still in the dark.
Most of those without power are Puget Sound Energy customers, and the utility has hundreds of linemen working to repair damage from last week's ice storm.
At the height of the storm on Thursday, more than 300,000 customers lost power across Western Washington as the weight of snow and ice brought down trees and branches across power lines.
Although repair work is continuing around the clock, PSE says it could take until the middle of the week to get everyone back on line.
Several school districts in the area canceled or delayed classes again on Monday due to road conditions or lack of power.
Lighter rain showers are expected on Wednesday and Thursday, but models show a high-pressure system moving into the area toward the end of the week that should bring us a sunny weekend.