The Mountain Housing Council's recent study updated the "average market-rate home price" to be $724,763 in 2018.
The Tahoe Sierra Multiple Listing Service reports the median and average home price. The median home price is the price that is midway between the least expensive and most expensive home sold in an area from January 1 until December 31. Median home price is considered more accurate as an indicator than an average price, which can be skewed by a few high priced home sales.
California: http://www.car.org/marketdata/data/housingdata/
United States: http://www.census.gov/const/uspricemon.pdf