Monday, July 18, 2011

Crossing the Dome

Heading back to our Littleton, Colorado, farm, we left Columbia on another warm, humid morning. West of town, the Missouri River had spilled across its floodplain, but, for the rest of our journey, the landscape would reflect the relentness heat and drought of the past month.

The hazy, humid air persisted through eastern Kansas, where the Flint Hills had faded to an olive green, but gave way to smoky air in central Kansas, where ranchers took advantage of relatively calm winds to burn their fields. In western Kansas and eastern Colorado, the thin air was free of haze but the intense sunshine evened the score and a strong, southerly wind produced a blast furnace effect. Indeed, wildlife was rarely encountered on this hot afternoon and herds of cattle either gathered in the shade of trees or billboards or, better yet, congregated in farm ponds.

These brutal conditions are the product of a massive, high pressure dome which continues to dominate the central U.S., diverting moisture and cooler air around its outer rim. Near its center, the sinking air heats up and cloud formation is suppressed; as one travels toward its outer regions, where the atmospheric pressure is lower, puffy clouds dot the clear blue sky. Finally, as we observed on our approach to Denver, storms ignite along the dome's outer rim, moving in a clockwise direction; today, these storms obscured the Front Range but did not penetrate the urban corridor, which remained within the dome's embrace. Over the past week, when the dome had not yet expanded to the base of Rockies, Metro Denver was deluged with monsoon rains, as storms rode northward along the dome's outer edge.