Why a structure that is perfectly sound in Redlands will not carry a Big Bear winter — explained plainly.
The single biggest difference between building in Big Bear and building down the hill is load. A roof structure that is entirely adequate in Redlands can be dangerously undersized at 6,750 feet, and the reason is straightforward: snow is heavy, and it accumulates.
Wet snow runs roughly 20 pounds per cubic foot. Three feet of it across a roof adds tens of thousands of pounds that the structure has to carry down through rafters, walls and foundation into the ground. Design snow loads here are multiples of what valley construction assumes. That drives heavier rafters, tighter spacing, engineered ridge and hip members, and connection hardware sized for real forces rather than convention.
Roof pitch and material interact with this. A steeper pitch sheds more readily, reducing accumulation — but it concentrates the shedding load somewhere, and that somewhere had better not be a deck, an entry or a gas meter. Getting slide direction right is a design decision, not an afterthought, and we have repaired plenty of railings and entry roofs destroyed by snow released off a slope above them.
Below grade, frost depth governs the foundation. Footings have to bear below the line where ground freezing occurs, otherwise frost heave lifts and cracks them through repeated freeze-thaw cycles. Big Bear requires deeper footings than most Southern California construction, which affects both excavation cost and the schedule — you want that concrete in before the ground freezes, not during.
Drainage is the quiet one. Spring melt moves a lot of water through these sites in a short window. Without proper grading, foundation waterproofing and perimeter drainage, that water finds the foundation and works on it every year. Crawl-space moisture, efflorescence on concrete and persistent musty smells almost always trace back to drainage that was never designed properly.
Wind exposure varies enormously across the valley. Open lots in Big Bear City and Lake Williams see loading that sheltered south-shore properties never do. Sheathing nailing patterns, hold-downs and roof-to-wall connections all need to reflect the actual exposure of the site rather than a generic detail.
None of this is a reason not to build here. It is a reason to build with someone who has done it repeatedly at this elevation. Every one of these requirements is well understood and routine — provided the person framing the house has spent winters watching what these conditions do to structures that were detailed for somewhere else.