To be fair Longview hit -20 in Jan 1930 though. Other parts of Western WA have had some crazy numbers on a few occasions.
Jan 1893 dropped to -10 in Woodland Park in Seattle.
Jan 1893 dropped to -15 near Mount Vernon
Jan 1950 dropped to -10 in Bothell
Jan 1862 had -5 to -10 readings all around the Puget Sound area.
Not to diminish Helene at all, but the Naselle Radar Station in SW WA hit 150 with the Columbus Day storm. Just to give an idea of how incredible that thing was.