My county, just across the river to the south has suffered from arrested development during the same period and is as light colored as your very northerly CA county.
Before, I couldn't find an affordable place to move to in Placer because of the boom, so now maybe I can move across the river due to the bust... I'm sure most of the darker coloration in Placer is due to the part closest to Sacramento, however.
I'm off to look for a forclosure in Placer County, tubebender!!!(either that, or a swap)
Placer County, THERE’S GOLD IN THEM THAR HILLS...