It really comes down to what you consider Nor Cal. To me that means the Feather, Shasta, Trinity and Klamath as your major gold bearing waterways and their tributaries. Dec 2005/ Jan 2006 hammered parts of the Klamath just upstream of the Trinity confluence but it thinned out at the confluence and parts of the Shasta at Dunsmuir were almost a gold moving event then too. To be a gold moving event we are talking about the biggest of the big boulders moving. These break up parts the bedrock and re-stratify the stream bed.
Not all parts of the river gravels may be put into play on every gold moving event. For the Klamath and the Trinity the last time was the 1997 flood. There is a very distinct flood layer that can pay well even though the bedrock has been "mined out" in some places beneath it. This is a melted chocolate color flood layer and sometimes has a purple tint to it. Pay attention to the colors of flood layers so when you talk to others you know what to look for. Not every flood layer is a pay layer.
Most seasons, even the heaviest season, are NOT gold moving as there is a lot of water over the whole season. What really moves gold is is the isolated storm events, a lot of water plus a butt load more in a short period of time is what it takes to move gold. For the areas that I mine in Nor Cal most gold moving events occurred during low water seasons or even droughts. These typically occur when there are fewer storms for the season but the storms were greater in intensity. Most of these occurred from a 1-2 punch. An arctic snow storm would occur followed by a Pineapple Express. When this occurs the water level is lower than normal at that time due to the low water season, the arctic storm would be colder than normal that would lay down a nice base of snow that wouldn't melt as fast due to the arctic effect. The Pineapple Express, which tends to be wetter, runs in with warmer air and water which melts all that snow that was just laid down. You wind up with basically 2 storms worth of water instantly going downstream. I have a major bridge that was washed downstream over a mile on one of my claims from such an event. Turned it into a ball of discarded erector set pieces like it was nothing! If the flood can do that then moving even the biggest of nuggets don't stand a chance. That said, it didn't break up all of the stream bed as there is still virgin pack under that flood layer in many places!
The power of this is extraordinary to say the least. Typically winter storms may get to 20-30 times summer flows but won't move gold. On some of my claims we typically see a 40-50+ x summer flows once a winter but that still won't move the gold. You really need 100+ x the summer flows to have an impact. There are always exceptions to this so you must dig through the history books to get the info. Talk to as many of the old timers still left for a wealth of info to learn the color of the flood layers worth checking out.
Modern dammed rivers rarely, if ever, have gold moving events anymore unless the dam itself lets go. Even when they do a “super flush” from the dam to help out poor Sammy the Salmon for spawning these only break up the overburden.
Sorry about the long response – you asked what time it is and I built you a watch instead – but it is nice to be chatting about mining again!
ratled
