Stick-house Smoke detector question

Well last night there was a change in the wind and now another season of Calif exporting it’s wildfire smoke (et al…) into Nevada - Ugg…

Our house is only a few years old, so is uber tight and insulated (as tested per code.)…Yesterday, the sky was fairly clear, but apparently after dusk the wind direction had changed…Last night 3 or 4 of the Kidde (home depot style) hard-wired smoke alarms went off last night (0030hrs), two of which were in rooms with their doors closed, and one within an expansive hallway…I then awoke suddenly and combed the entire house and yard and even the attic but saw no issues and had yet to smell any smoke…Though it seems the nearest fire is of a considerable distance away, this morning I noticed some fine ash on the patio, and the air is BAD here today…

But in the aftermath, what’s most curious to me is that all of these smoke detectors sounded at the exact same time, and I don’t know by what mechanism they could do this in unison??…Any ideas would be greatly appreciated, Thanks,

P.S. Sure is some tough news for those affected :(

3 tons