Sure, there's one in Burien under the power lines.

I think you're referring to Sequoiadendron gigantea rather than Sequoia sempervirens. Common mistake.

Sequoiadendron (one word) grows in the western side of the Sierras. Sequoia sempervirens (two words) grows along the northern California and southern Oregon coast.

Mike

any tree... that gets its leader broken ... responds by putting up one.. and usually more leaders ...

this is not something unusual.. nor rare ... its a genetic response to damage ...

you should remove all but one leader ...

ken

It's not very common in Sequoiadendrons. Usually one leader will take apical dominance straight away and leave the others behind. I don't know how familiar you are with these trees but if you look around, you will seldom, if ever, see one with more than one leader after it attains any size. I don't remember seeing any in the groves I walked in in California. Calaveras, Muir, etc.

Two trees can grow side by side rather well though for centuries.

Mike