Spring is normally when Safari West gradually prepares for the busy summer season.
But this year, a stampede of visitors arrived at the African wildlife preserve near Santa Rosa earlier than ever, and shows little signs of letting up.
"This year we were almost sold out every day in March. We've never experienced that before," said Aphrodite Caserta, a spokeswoman for the preserve.
Visitors to Sonoma County spent $1.47 billion in 2011, according to the latest figures released last week by Visit California. That's a 9 percent increase over 2010, and the most on record since 1992, when such data started to be collected.
Industry experts say the trend reflects a better economy, people traveling again and Sonoma County ever-more coming into the national consciousness as a desirable destination.
"Sonoma County is such a hot spot to vacation," said Pauline Wood, who co-owns the KOA Kampgrounds in Petaluma with her husband, Chris. "Very few places have the weather we have and so many things to do when people stay at campsites or hotels."
The increase in visitor dollars, which in 2011 equaled 19 percent of tax revenue generated in Sonoma County, also reflects an average increase in lodging costs.
The average daily room rate in the county rose 3.6 percent last year to $116.80, according to Smith Travel Research, which tracks the sector.
Wood said the Petaluma campground raised rates this year for the first time in three years, a 2 percent increase she said was necessary to offset higher costs to run the site.
She said the price increase hasn't hurt business, however, and that the most explosive growth has been with the site's 20 lodges, which offer such hotel-style amenities as linen service, kitchens and gas-powered grills.