Washed out roads and blocked rail tracks in Canada’s westernmost province are fueling a lumber price rally as key supplies risk being stuck just as home builders start piling up materials. Lumber futures in Chicago jumped 6.3% to $757 per 1,000 board feet on Thursday, the highest since Oct. 25, after a once-in-a-century storm forced British Columbia to declare a state of emergency.  The extreme deluge washed away and blocked parts of the province’s main highways, closed the tracks of Canada’s two major railways, flooded many areas and ...