California’s recent atmospheric river brought much-needed rain, but it also delivered a wave of unexpected pest activity. While storms help replenish reservoirs and ease drought conditions, they also disrupt the natural habitats of many pests. When their usual hiding places flood or become unstable, pests do what any living thing would do: they move to higher, safer ground.
Unfortunately, that often means they move closer to homes and sometimes right into them.
Clark, your friendly neighborhood pest, rodent and termite expert, wants California homeowners to understand why this happens, what to expect, and how to protect their homes during and after heavy rains.
Why Storms Push Pests Toward Homes
When an atmospheric river dumps several inches of rain in a short time, it dramatically changes the environment around your home:
1. Flooded Harborage Areas
Rodents, insects, and crawling pests rely on dry, protected spaces -burrows, soil nests, leaf litter, mulch beds, and tree bark to survive. When those areas become saturated or fully submerged:
- Rodents abandon underground nests
- Ants evacuate flooded colonies
- Cockroaches and spiders seek new shelter
- Earwigs, sow bugs, and beetles get pushed above ground
These displaced pests begin looking for the nearest dry, warm refuge. Homes with convenient entry points - no matter how tiny - quickly become attractive.
2. Disrupted Food Sources
Heavy rains wash away crumbs, seeds, vegetation, and other materials pests rely on outdoors. This scarcity can drive:
- Rodents to search garages, patios, and kitchens
- Ants to forage aggressively inside homes
- Raccoons and skunks to explore trash bins or yard structures
If pests find food indoors even once, they often return.
3. Increased Moisture and the Pests That Thrive in It
Standing water and prolonged soil saturation create ideal conditions for:
- Mosquito breeding
- Termite activity (especially subterranean termites, which need moisture)
- Slugs and snails
- Earwigs and millipedes
Even excess moisture under a home from clogged gutters or poor drainage can fuel population growth.
Which Pests Are Most Active After Heavy Rain?
While nearly all pests react to heavy rain, California homeowners tend to see increased activity from these pests:
- Argentine ants indoors, especially in kitchens and bathrooms
- Roof rats and Norway rats seeking shelter in attics, garages, and crawl spaces
- Cockroaches (particularly American and Oriental varieties) driven out of storm drains
- Spiders entering living spaces as their prey shifts
- Sow bugs, pill bugs, earwigs, and millipedes emerging from saturated soil
- Termites, whose swarming season often aligns with periods of moisture, followed by warm, sunny days.
What Homeowners Can Do Now
The good news? A few proactive steps can dramatically reduce pest pressure.
Seal Up Access Points
Check for gaps and cracks:
- Around doors and windows
- Where utility lines enter
- Under eaves and rooflines
- In foundation vents
Mice can squeeze through openings the size of a dime.
Improve Drainage
Clear gutters, extend downspouts, and eliminate standing water. Damp soil and clogged drainage are magnets for termites, mosquitoes, and other pests.
Reduce Outdoor Harborage
Trim vegetation, remove leaf clutter, and elevate stored items. The fewer hiding places around your home, the fewer pests will stay after the rains.
Store Food Properly
Inside and outside, keep food sealed. Pet dishes, birdseed bags, and open trash cans are often the first attractants for post-storm rodents.
Schedule a Professional Inspection
A highly trained, licensed Clark Pest Control technician can look for:
- Pest entry points
- Early signs of termite moisture activity
- Rodent nesting clues
- Conditions that may worsen with future storms
Catching issues early can prevent long-term infestations.
Clark Is Here to Help After the Storm
Heavy rains don’t just bring water - they shift pest behavior in ways homeowners can feel for weeks or months afterward. If the atmospheric river left you dealing with new or increased pest issues, Clark Pest Control is ready to help restore your peace of mind.
Want a post-storm inspection or advice tailored to your home? Call Clark at 800/WE-NEED-YOU, or email clarkcares@clarkpest.com to schedule a service visit.
Until next time, the pest management professionals at Clark thank you for helping keep unwanted pests out of your home and yard.