The fairways may be wider at Shinnecock Hills for the 2018 US Open compared to when it last hosted 14 years ago, but the rough just off the fairways may be taller, thicker and nastier than ever. That's in part because the USGA sodded-in more than 5 acres of fescue rough, replacing pulled up fairway (and putting that in unique storage) with the stuff.
Not only is the rough, located just off the first cut of rough off the fairway, thick and healthy, but it's so tall it makes finding the ball difficult. Several times, players have needed additional help to find their ball in the rough. In a number of cases, players or spectators or media have stepped on golf balls they're looking to find.
Of course, this is natural when this particular rough at Shinnecock Hills can be 12 inches tall. At a minimum, this rough is at least ankle-high, or about 4 inches tall. The length varies around the course, depending on how much penalty the USGA believes a player should experience for hitting a bad shot in to a particular area.
The length of the Shinnecock Hills rough truly doesn't matter all that much after about 6 inches. It's at that length a golfer's club will be easily grabbed by the grass as a player tries to accelerate the swing through the ball. Longer than that, however, it may be impossible for a golfer to hit the golf ball on purpose with their stroke. In some cases, they may only move the ball by virtue of rustling the surrounding grass.
The best play out of the deep rough is to find the shortest path back to the fairway, hoping to hit the ball far enough to get back into the short grass. Trying to advance the ball much more than that could lead to leaving the ball in the thick stuff, meaning a player will face an additional penalty for finding the rough.
Beyond the thickest of fescue that was sodded in, the fescue rough is still lengthy in places but more wispy. That grass gives the golfer who misses big a better chance of ending up with a lie that will allow them to advance the ball toward the green, if not find it.
Players would be well-advised to follow the mantra of the US Open for years: Miss big or don't miss at all.