Sometimes, morels will come up in flushes each time a rain occurs. Sometimes, they will come up without a rain, but they will then be delayed a couple of weeks. Be careful of false morels, sometimes called brain mushrooms. They produce a toxin. It is usually not lethal in this country but should be avoided.
False morels are rounder and lower to the ground, and the ridges are more rounded, like brains.
Be careful about storing morels a long time before eating, unless they are dried or precooked and frozen. Otherise, bacteria grow on them, which can make a person sick, but not seriously ill. The bacteria are probably Psuedomonads. Store in paper bags, which absorb moisture, but avoid plastic, which causes moisture to accumulate. Even when cooking kills bacteria, it leaves a moderately problematic endotoxin with gram negative bacteria, which grow on morels.