The golf legend documented the scary incident on Twitter Sunday morning, saying he and a bunch of other guests were evacuated near Medinah, IL -- where Phil's participating in the BMW Championship as part of the FedEx Cup Playoffs -- after their hotel got hit by a lightning bolt ... which apparently sent part of the facility up in flames.

Phil wrote, "How’s this for crazy? My hotel was struck by lighting, I was on top floor,we were evacuated and the place is on fire(only thing of mine on fire this week.) I can’t get back into my room and may miss my tee time because I am without clubs and clothes."

His fourth-round tee time (with Brooks Koepka and Dylan Frittelli) was scheduled for 11:52 AM ET, and he was being shuffled out of his hotel a little more than an hour before that.

Luckily for him, Phil reportedly made it to the tee just in the nick of time -- and was later escorted back to his room and was able to retrieve his gear. Phil shouted out the EMTs who helped, writing ... "EMT's were awesome! I'm going to make it. Turns out my clubs acted as a fire retardant. Lucky me."

Now, the bummer ... Phil isn't doing too hot in the tournament right now -- he's in 47th place as of this writing ... and it'll be an uphill climb to break into the top 30 he needs to be in to move on.

Also important ... it doesn't sound like Phil notified his family of the emergency, including his ma -- which his sister, Tina, made him well aware of on Twitter.