|Paul, the vines are just as dangerous -- maybe even more so -- than the leaves. Winter or summer, you can still get the rash. My advice is to go online and purchase some Tyvek recycled biohazard suits, thick rubberized work gloves and methodically pull it up from the ground.
Always use common sense when dealing with this stuff. The biohazard suits work very well and they're not too expensive. I got three sets of hooded coveralls, boot covers, etc. for about 50 dollars and was successful in getting rid of the ivy in my yard. These are the same suits that PI removal companies in my area (NY) use when they go on service calls.
50 dollars might sound like a lot, but there's no way to put a price on NOT getting poison ivy. It's as miserable as it gets. But I'm sure you know that by now. Just be careful, use common sense, and go slowly and carefully. Try your best to get the roots as well, or it will grow back.