Porte was distanced as the pace was first ramped up by EF Education First with 38 kilometres to go, with further surges from Decuninck-Quickstep and then Team Ineos really putting the hammer down.
Porte was left scrambling with a number of other favourites to close the gap, including Thibaut Pinot (Groupama-FDJ), Jakob Fuglsang (Astana) and Rigoberto Uran (EF Education First), whose team started the whole thing.
Porte talked to SBS after the stage about how the wind and the other teams turned the race into one of carnage.
"Yeah, it did," Porte said of the race being thrown into disarray by the wind. "I think we knew that it was coming, but when they put it in the gutter there I was the last guy not to get across. It's disappointing but the race goes on.
"It's just a power thing to be honest, when they put it in the gutter on the left hand side it's a different thing and I obviously just wasn't up to it today.
Porte joined the second group on the road, containing a number of favourites and their team-mates. The group worked very hard and was able to come back to within 13 seconds of the rear of the peloton, but couldn't quite close down the final gap to get back on terms with the leaders.
The gap then began to balloon as the race got within 15 kilometres of the finish and the impetus went out of the chase, with the gap growing all the way into the finish line where they stopped the clock one minute and 40 seconds in arrears of the lead riders.
Trek-Segafredo sports director Kim Andersen was downcast after the race, but indicated that the squad would continue to fight to Paris.
"It's not good to lose time, it's more than one minute. I still believe that in Paris, there will be a big difference between the first five. But it was a day where we could win time and we lose, so it's not perfect."
"We had a very nice Tour up to now, today is not a nice day because we lose a bit of everything in five kilometres.
"We will do our best and keep focusing. There's a long way to Paris and all the mountains are still coming, you can see everyday that something can happen."
Porte now sits three minutes and 59 seconds behind race leader Alaphilippe, more relevantly two minutes and 47 seconds behind defending champion Geraint Thomas, who now sits second overall and the best of the likely general classification contenders.
"There are quite a lot of GC guys in my boat," said Porte, "so I'll guess we'll have to do something... but there's still a lot of hard racing to come."