Those images show a very distinct canker, indicating the presence of either a fungal or bacterial disease. Have you seen anything that matches the description of white pine blister rust (article below)? That is a fairly common disease, but I do not see the characteristic yellow blisters (that release orange spores). I will touch base with some others on our team for additional input, but my initial thought is that the trees are weakened by stressful growing conditions, making them more susceptible to diseases they would ordinarily resist.

https://www.canr.msu.edu/news/white_pine_blister_rust_damage_showing_up

I had two other tree experts review the photos. There are a few possibilities, including Zimmerman pine moth (but they tend to avoid white pine, which is too pitchy for them) and pitch mass borer (but they tend to be higher up in the tree). White pine blister rust is the most likely culprit, though there could be multiple things going on.

There really isn't much you can do for them, other than any actions that promote drainage. Fungicides are unlikely to be effective, and we don't recommend treating the ground or soil. Whatever this is, it is likely to spread to the other white pines. I would recommend removal of any tree with evident disease in the main trunk, and pruning off infected branches from other trees that do not have disease evident in the main trunk. Only prune when the foliage is dry and there is no rain in the forecast for several days, to reduce the risk of spreading disease. Sterilizing pruning tools between cuts is not a bad idea, either.

If you would like to know for sure what the issue is, you could consult with MSU Plant and Pest Diagnostics. There is a fee for their services, but they can evaluate a sample for insects or disease and for various pathogens. You would need to contact them first to find out exactly what sample material would be required.