Weather Permitting

Just about any invitation to visit an archaeological excavation is followed by the caveat “weather permitting.” The wording may make readers skeptical of archaeology’s adventuresome reputation. Surely a bit of foul weather wouldn’t deter a real archaeologist?! In fact, archaeologists keep a close eye on the weather, though perhaps not always for the reasons one might think. So which are the weather conditions that are most “archaeologically prohibitive”?

This time of year, we think a lot about temperature. While our current field crew is evenly divided over which is worse: heat or cold, temperature is really not a limiting factor. We work with the mercury hovering at either extreme. Here’s a fun fact: Colonial Williamsburg’s horses are retired from the streets when the temperature hits 95 degrees. We certainly do not begrudge our 4-legged colleagues this extra care (after all, they do work on blacktop, pulling heavy loads). It is not lost on us, however, that no such “magic number” has been established for archaeologists! Frequent water breaks and occasional popsicles help to keep the heat in check.

At the other end of the calendar, winters in Tidewater Virginia, while damp, are not really cold enough to permit the ground to freeze (at least not deeply enough to be a problem). While few archaeologists would choose winter excavation, it is sometimes necessary. The greatest issues involve fine motor skills: when fingers are too frozen to grip a pencil, an archaeologist’s most important tool is out of commission. Adhesive heat patches and substantial quantities of coffee are typical remedies…though we did try a novel approach to cold-weather digging during the winter of 2012. Readers of the Armoury blog may remember that archaeologists worked inside the reconstructed Mary Stith Tin Shop that winter, removing the floor, but leaving the central heating system intact. This technique may have potential for the future!

Rain presents our greatest challenge, not because of inconvenience to the archaeologists, but because of potential damage to the site. As the ground becomes soggy, movement across the site leaves footprints embedded in carefully exposed soil layers. Virginia summer weather often follows a familiar pattern: heat and humidity build during the day, culminating in a late day thunderstorm. To prepare, our sites are carefully tarped each afternoon, but a typical thundershower can result in an hour or more of bailing and clean-up the following morning. Intense rain is more than an inconvenience. It can collapse the edges of postholes and side walls, undermine brick foundations.

So dry weather is what archaeologists hope for? Hmmm…. not exactly. Very dry conditions bake the soil, making it difficult to excavate. More importantly, lack of moisture bleaches soil colors, leaving the dirt hard to “read.” As the summer wears on, the faint mottling that indicates the former location of a fence post or a trench becomes nearly undetectable. During the summer of 2010, there was so little rain (and so much heat) that the 18^th century perimeter fence surrounding the Armoury virtually vanished from archaeological view. One of the most important pieces of archaeological equipment, therefore, is a sprayer or a hose with a spray nozzle. Gently moistening the ground brings out color differences, helping archaeologists to see the features they need to excavate.

So the next time you see the words “weather permitting,” understand that you are being warned that the archaeologists are unlikely to be working in the rain. But you will also have a finer appreciation for the complex relationship between archaeology and all of the elements!

Meredith Poole, Staff Archaeologist