The route which brought Mark to this point is also full of geographical interest..After leaving San Diego, the Inter State 8 climbs up through the Laguna Mountains (referred to in yesterday's posting) to a height of around 2000m. Part of today's journey through the mountains took Mark through the Cleveland National Forest, the most southerly national forest in the USA. According to the forest website "The Cleveland National Forest is a very special place in southern California. The forest is a haven for wildlife and plants. The wild shrub and tree-covered mountains are remnants of a landscape that at one time covered most of southern California. With the settling of missions, towns, cities, and suburbs, populated areas now surround the mountains. Natural areas for plants and animals have become smaller and smaller, and in some cases, have disappeared." Mark may have seen evidence of severe wildfires (associated with the Santa Ana winds described in this posting )which frequently sweep the area - some as recently as last year. The Cleveland forest was also the location of the Cedar Fire, the largest wildfire in California history which devastated 720 sq miles of the forest in 2003. A good general impression of the scenery of the Laguna Mountains can be gleaned from the image above and from the following borrowed from the Panoramio layer in Google Earth. Mark will certainly have cycled across this viaduct at some point yesterday.Climatically, the mountains to the east of San Diego are hugely significant as they act as a barrier to the inland penetration of oceanic influences. Any moisture which on-shore winds may bring to the south of California is trapped to the west of the mountains. This, added to the fact that the prevailing winds in this region are north easterlies (and hence dry as they are coming from the heart of the continent) means that there is desert to the east of the mountains.
The altitude of the mountains does have its benefits, however, as I spotted when I looked more closely at this strange pattern which was visible from the air. This is a 2 mile line of 25 wind turbines (and their shadows!)
Some investigation reveals them to be the Tecate Divide wind farm with the largest capacity wind turbines in the USA. They also represent the first large-scale commercial wind farm on Indian lands in the US. The tribe will collect fees on a 20-year lease, plus royalties from electricity sales to San Diego Gas & Electric.Travelling east and descending from the mountains, Mark would have passed within a couple of kms of the heavily protected Mexican border and into the very arid environment of the Colorado desert to the east (shown below within the dotted yellow line). ... which, understandably is very sparsely populated except where there has been reason to settle as here in the enigmatically titled 'Plaster City'