I found these weird dirt tunnels running up the support beams in my basement. I poked one and it crumbled, but it looks like they go all the way to the subfloor. Is this serious?

Crumbling Tubes Are Still a Serious Problem
Even if the mud tubes crumble easily and appear inactive, they can still signal a serious problem. Crumbling tubes might mean termites have moved to a different part of your home or have temporarily stopped using that particular path but are still present in your home.
Additionally, old tubes can still indicate significant past damage, which can weaken structural integrity even if the infestation is no longer active. It’s important to conduct a thorough inspection to ensure there are no remaining termites and