When it hits
Day 30 on the Student's run
No warning comes first.
Starts with Mold Attack, ends with 
Rain Ends.
The same on every run: Wage Slave, Warehouse Manager
What comes
No zombies: this crisis is about the weather, sickness or pests, not a siege.
From the game files1
Crisis 130
| id | 130 |
|---|---|
| CrisisID | 130 |
| StartEvent | [52647] |
| EndEvent | [52648] |
| Des | Crisis_Des_130 |
| Des_Local | 霉菌 |