Last Oct 30th (2018), I found myself at Lighthouse Pt in New Haven, CT during a healthy passage of buteos and eagles. These large raptor days are all too scarce at Lighthouse, where it takes a well-timed late Oct-early Nov cold front to produce a day like this along the Connecticut coast. One of the Red-tails that day, a juvenile bird, was strikingly pale below. The bird wasn't terribly low, was picked up when it was already just about overhead, and streamed westward across the harbor, never allowing for a topside view. I did manage a handful of poor ventral images, which show some features that suggest a Krider's intergrade.
In the photos below, note the overall ghostly underparts, in particular the faint patagial. A zoom-in on the face strongly indicates a whitish cheek that offsets a dark malar, which is another Krider's-like feature. As Red-tail expert Brian Sullivan notes, you can't say much without upperpart photos in this case. Wherever it came from, a unique bird for sure, and outside the norm for borealis.