Big Falls could very well be Southern California's tallest year-round waterfall with a reported cumulative drop of 500ft.
In our experiences, there was no way to see the entire waterfall from any one spot since it came down in multiple tiers as it twisted and turned on its way down with plenty of canyon walls and trees in the way to ensure we never got a totally clean view. However, just the main tier alone was attractive and tall (maybe some 150-200ft or so) and certainly worth the effort to drive all the way here. In fact, we liked this waterfall enough to place it on our Top 10 List of Best Southern California Waterfalls.
The first time we attempted to visit this waterfall was back in late Spring of 2005 when they closed the trail to the viewpoint below the falls. During that trip, we had to settle for views from across the canyon at the Forest Falls community. We would eventually figure out why the trail was closed (which we'll get to shortly). Five years later, we came back in the Summer, and we were pleasantly surprised at its satisfying flow (especially considering it was August and in the middle of fire season).
Moreover, the trail was open (and pretty busy). So after parking the car (and displaying a Forest Adventure Pass), we followed the trail to the left along Mill Creek before we had to cross it. The crossing was nothing more than rock hopping to stay dry, but I could totally imagine how it could not be safely crossed during the peak snowmelt period of Spring. In fact, our Spring of 2005 visit was one such Spring where it followed a heavy-rainfall/snowpack Winter. That would explain why it was closed on our first visit.
Speaking of high rainfall years, in Summer of 2010, we were having June Gloom even in August so it seemed like the waterfall's flow behaved more like it was July or something. It also helped that we had a wet Winter in 2010.
Anyways, once we were beyond Mill Creek, we were able to scramble onto the rocky delta of Falls Creek where we could look high up at the main section of the falls. It was a good thing I had a telephoto lens this time to capture it. Otherwise, the falls would look pretty small with most normal zooms. We also checked out some of the smaller cascades comprising the lowermost sections of Big Falls.
Behind the Hazardous Area sign, the trail continued to climb uphill for a brief moment before terminating at a railed overlook providing a slightly better view of the main section of Big Falls as well as some other cascades twisting and turning through the canyon. This would typically be the end point of the excursion, which would end up being about 0.6 miles round trip from the car park.
Now while I don't advocate scrambling off trail, Mom and I followed a couple of middle-aged guys who indirectly showed us the way up even higher than the official viewpoint. This involved a bit of stream walking (good thing we had Gore-tex boots) and rock scrambling all the while avoiding poison oak and a couple of fallen trees. After another 10-15 minutes more of scrambling, Mom and I ended up seeing a couple of tall vertical hidden tiers that would've otherwise not been seen.
It were these sections of the falls that really reminded me of a taller version of Fish Canyon Falls and made the scramble worthwhile. However, it was dangerous enough where both Dad and Julie stayed behind (and I definitely wouldn't recommend children, pregnant women, nor seniors try it). Had those two guys not have already scrambled up and gave Mom the idea of following them, we wouldn't have made the attempt. Thus, I could totally envision why fatalies have happened here before.
Still, I thought I had seen worse scrambles than this, and if you come prepared and respect Nature enough to be willing to turn back when the conditions wouldn't allow for you to proceed, then perhaps it might be worth a look to see if the scramble is for you. But again, be cognizant of the rockfall danger as well as the slippery rocks.
To get here, take the I-10 east until you reach State Hwy 38 (Orange Ave). At first, Hwy 38 passes through the suburban streets of Redlands, but eventually, it becomes a more full-blown mountain highway. After about 15 miles or so, Hwy 38 junctions with Valley of the Falls Drive at a hairpin turn.
Take Valley of the Falls Drive on the right, and then follow this road through the Forest Falls community before turning left onto the large car park area for Big Falls (it's just beyond the end of town). Parked vehicles must display an Adventure Pass here, and we were able to purchase one on the spot at this car park.
It took us about 90 minutes of driving from around the 60/57 Freeway junction towards Forest Falls.