150-250 cfs III
250-500 cfs III+
500-650 cfs IV-
650+ cfs ?
These flows apply for the last 8 miles of the river only. The majority of this flow in the river comes in from Deep Creek at this point. A "one third rule" has been suggested saying that around 1/3 of the flow comes from the North Fork of the Virgin and the rest comes from Deep Creek. This is not a reliable rule of thumb. The Springdale Gauge provies little information about the flow for the first 8 miles of the run.
Also note that this flow fluctuates throughout the course day. The peak is around 5am in Springdale, which means its probably sometime in the early early morning in the Narrows. Because of this, throughout the afternoon flows should increase. Be prepared for 100-150cfs more than the gauge reads at the ranger station in the morning.
Due to the narrow constricted nature of the canyon, small variations in flow can change the character of the canyon significantly. At levels above 500cfs the river becomes pushy which can make avoiding numerous logs more difficult. Most descriptions will consider this run class III, but at higher flows class IV moves are required to avoid dangerous wood. More water in the canyon can not spread out horizontally, so the river will only become deeper and faster. Carefully consider the ability of your group before putting in at high flows.
For the first 8 miles of the run, you will get a visual when you get to the put-in. Look at the amount of water in the river, that is the flow you will have to work with for the next 8 miles. It won't be much, so you'll likely be scraping/dragging/pulling/carrying your boat for this stretch. This flow drops throughout the course of the day. Putting on as early as possible is the best way to insure the most flow for this stretch, looking at gauges probably won't help. Getting to the put-in at sun up is highly recommended. Putting in an our or two earlier with headlamps would not necessar ily be a bad idea. DO NOT get your permit the morning of and end up putting in at 10/10:30. You likely won't even have enough water to run the waterfall, one of the highlights of the trip.
A flow forecast is here:
Utah SNOTEL SWE:
|NORTH FORK VIRGIN RIVER NEAR SPRINGDALE, UT|
|usgs-09405500||500 - 650 cfs||III||00h31m||~ 50 cfs (too low)|
Reports give the public a chance to report on river conditions throughout the country as well as log the history of a river.