During winter in New York, property owners and the city dump tons of salt onto the streets to prevent icing. As the snow melts, the salt washes down into the drains, where it corrodes subsurface electrical wiring, leading to short circuits with sometimes fatal consequences.
This video, filmed on my street, illustrates why you don't want to step on anything metal in a New York winter.
When I went back a few hours later, someone had torn down all the caution tape and parked an SUV on top of this grating. Some people's survival instincts are not everything they should be.