For our first four years, outdoor inventory at the Glory Road yard was rows of reconditioned totes stacked two-high in the open air. We had a temporary canopy over the food-grade rows. We had been told by an engineer in 2018 that the canopy was rated for 24 PSF live load.
On the night of December 13, 2022, we got 26 inches of wet snow in 14 hours. The canopy collapsed. Six totes were damaged but recoverable; two were destroyed. No one was hurt because no one was in the yard at 3 a.m. on a Sunday. We had been lucky.
What we did wrong
The canopy had been rated for 24 PSF live load when it was new. By 2022 the steel had spent four winters out, the connections had loosened slightly, and the actual load capacity was probably closer to 16 PSF. We had assumed nothing had changed because nothing visibly had changed.
We had also been stacking two-high under the canopy because it let us fit more inventory. A collapse onto a single-stack row would have damaged half as many totes.
What we changed
We tore down the temporary canopy and replaced it with a permanent steel-truss structure rated by an engineer in 2023 for 70 PSF live load — well above any plausible snowfall in our area.
We instituted a hard rule: any outdoor stacking is single-tier between November 1 and April 1, regardless of snow forecast. The capacity hit is real (about 35% fewer outdoor positions). The risk hit is bigger.
We inspect overhead structures annually, not assumed.