At its northernmost limit, the California coastline suffered a winter of brutal winds pitched against iron- clad fog, and roiling seas whose whiplash could scar a man’s cheek as quickly as a cat- o’- nine- tails. Since the Gold Rush, mariners had run aground, and those who survived the splintering impact were often pulped when the tides tore them across the terrible strata of the volcanic landscape. For protection, the State had erected ascore of lighthouses staffed with teams of three or four families who rotated duties that lasted into the day and into the night. The changing of the guard, as it were, was especially treacherous in some locations, such as Crescent City, accessible only by a tombolo that was flooded in high tide, or Point Bonita, whose wooden walkway, even after the mildest storm, tended to faint dead away from the loose soil of its mountaintop and tumble into the sea.

Until the advent of navigational radio, communication with the mainland was spotty. God help the man who broke his leg on the Farallon Islands between the weekly supply- ship visits. But the peril of the European War had meant Crosley crystal- receiver radio sets and quenched spark systems with an eight- hundred- mile range for all who lived and worked on the coastlines, and so, on Sunday, November 12, 1916, just below the Oregon border, at the St. George Reef Lighthouse, eight miles off the California coast, there began an explosion of radio, telephone, and telegraph operations unprecedented in American history.

At high tide, roughly five o’clock in the morning, it was over an hour before dawn. The sweeping eighty- thousand- candlepower light from the third- order lens cast the frothing sea from shore to...