Topography
Although not particularly high compared to many other mountains, the Cascades look and feel high because they rise steeply from very low valleys. This immense local relief makes them quite impressively mountainous. Valley elevations are often below 2000 feet even in the heart of the range, with surrounding peaks soaring 5000 or more feet higher within the space of a couple of miles. Elevations in the Alpine Lakes region range from less than 1000 feet in low west side valleys to 9400 feet atop Mt. Stuart, the highest peak in the area.
It's worth noting that, in common with many “middle aged” mountains around the world, the Cascades usually follow the pattern, over long timescales, of sustaining mountain heights of about 2000 feet above local timberlines. Forests and their biomass hold mountains together, greatly reducing erosion. But upthrust is still ongoing, and mountains in most places have difficulty sustaining heights more than 2000 feet above timberline, since erosion is much greater above the zone where forests form a skin on the mountains, gluing them together.
This can easily be seen in the Alpine Lakes region. Forests generally need average summer growing season temperatures of no less than 50 degrees Fahrenheit, or 10 degrees Celsius. On the western front of the range, cool marine air and frequent clouds keep summertime temperatures down. Timberlines are usually around 5000 feet or a bit higher. Few mountains rise above 7000 feet. Moving east, the marine air and clouds diminish, allowing warmer summertime temperatures and higher timberlines, often 6500 to 7000 feet. A good number of mountains in the eastern parts of the range reach heights of 8500 to 9000 feet.
It's worth noting that, in common with many “middle aged” mountains around the world, the Cascades usually follow the pattern, over long timescales, of sustaining mountain heights of about 2000 feet above local timberlines. Forests and their biomass hold mountains together, greatly reducing erosion. But upthrust is still ongoing, and mountains in most places have difficulty sustaining heights more than 2000 feet above timberline, since erosion is much greater above the zone where forests form a skin on the mountains, gluing them together.
This can easily be seen in the Alpine Lakes region. Forests generally need average summer growing season temperatures of no less than 50 degrees Fahrenheit, or 10 degrees Celsius. On the western front of the range, cool marine air and frequent clouds keep summertime temperatures down. Timberlines are usually around 5000 feet or a bit higher. Few mountains rise above 7000 feet. Moving east, the marine air and clouds diminish, allowing warmer summertime temperatures and higher timberlines, often 6500 to 7000 feet. A good number of mountains in the eastern parts of the range reach heights of 8500 to 9000 feet.
Geology
Highly fractured granitics are the most common rocks in the Alpine Lakes region, although sedimentary, metamorphic, and igneous rocks are also present. The Cascades have been called one of the most geologically diverse mountain ranges on Earth, where almost every type of rock can be found. Yet there is an almost total lack of minerals in forms and quantities that can be commercially mined.
Old mines do indeed dot the landscape of many parts of the Alpine Lakes area. But only one, the Sunset mine northeast of Index, is believed to have turned a profit. Of the many others, most were little but dreams, dreams that ended up dying after lots of expensive, dangerous and backbreaking work. A few of the deposits had some high quality ores, but never in quantities sufficient to be viable for very long.
Acid drainage can still be a problem from some of these mines. But fortunately, the Cascades have been largely spared the kind of river poisoning, toxic legacy that plagues so many places with abandoned mines. The Cascades are a good place for rockhounds, not so good for prospectors.
Glaciation has helped form the landscape of the Cascades. Many valleys exhibit a U shaped cross section, characteristic of recently glaciated areas. Hundreds of cirques (bowls,) and related glacially carved features such as horns and narrow ridges occur at higher elevations. Most of the lakes in the region are in cirque basins between 3300 and 6000 feet in elevation. Morainal deposits of gravels and other glacial debris are found along the edges and outlets of U shaped valleys, and form dams at the outlets of many cirques, creating lakes. Some valleys were dammed by lobes of the Puget glacier pushing up into the mountains, resulting in lakebed clay deposits. This gives the Middle Fork Snoqualmie river in particular a greenish color during times of high water. Higher elevations are mostly bare rock, with meadows frequently found among timberline trees and some distance higher.
There are over 600 natural lakes in the region, covering over 6000 acres, with the average lake surface area being 10 acres or less. Many remote lakes far from trails offer excellent angling for introduced fish. Glaciers and permanent snowfields cover perhaps 3 square miles.
Old mines do indeed dot the landscape of many parts of the Alpine Lakes area. But only one, the Sunset mine northeast of Index, is believed to have turned a profit. Of the many others, most were little but dreams, dreams that ended up dying after lots of expensive, dangerous and backbreaking work. A few of the deposits had some high quality ores, but never in quantities sufficient to be viable for very long.
Acid drainage can still be a problem from some of these mines. But fortunately, the Cascades have been largely spared the kind of river poisoning, toxic legacy that plagues so many places with abandoned mines. The Cascades are a good place for rockhounds, not so good for prospectors.
Glaciation has helped form the landscape of the Cascades. Many valleys exhibit a U shaped cross section, characteristic of recently glaciated areas. Hundreds of cirques (bowls,) and related glacially carved features such as horns and narrow ridges occur at higher elevations. Most of the lakes in the region are in cirque basins between 3300 and 6000 feet in elevation. Morainal deposits of gravels and other glacial debris are found along the edges and outlets of U shaped valleys, and form dams at the outlets of many cirques, creating lakes. Some valleys were dammed by lobes of the Puget glacier pushing up into the mountains, resulting in lakebed clay deposits. This gives the Middle Fork Snoqualmie river in particular a greenish color during times of high water. Higher elevations are mostly bare rock, with meadows frequently found among timberline trees and some distance higher.
There are over 600 natural lakes in the region, covering over 6000 acres, with the average lake surface area being 10 acres or less. Many remote lakes far from trails offer excellent angling for introduced fish. Glaciers and permanent snowfields cover perhaps 3 square miles.
Climate
The abrupt mountain wall of the Cascades greatly affects local climates. Moist air masses moving east off the Pacific ocean rise and cool as they encounter the Cascades, wringing water out of the clouds. On many a sunny afternoon along Puget Sound, the view to the east is a wall of grey. From 35 inches per year at Seattle, annual rainfall amounts rise rapidly as one approaches the mountains, to 80 inches in the town of Index and as much as 190 inches on some west side mountains. Further east, levels drop to 80 inches at Stevens Pass, to 25 inches at Leavenworth and 10 inches at Wenatchee.
From the lush green west, to the savannahs and semi-arid steppe grasslands of the east, the look and feel of landscapes is determined largely by rainfall amounts. But those numbers don't always tell the complete story. From the western front of the range, and inland for a widely varying number of miles, summertime marine clouds can keep things from drying out even in periods of little rain. When these clouds meet the mountain forests, fog drip can contribute substantial moisture to the trees. The number of days with these clouds diminishes with every mile east from the western mountain front. Thus, places such as the Beckler valley and lands east of it near Skykomish, while still receiving high annual rainfall, are sunnier during the summer than places to the west and forests there tend to be a little more open and less brushy.
The pattern of Cascades rainfall is seasonal, falling mostly from late October to early May. Snowline varies with temperature, with areas above 2500 feet receiving considerable snowfall most winters. Snow levels in weather forecasts tend to be accurate for the western mountain front only. Farther into the mountains snowlines are usually lower, and valleys penetrating deeply into the mountains receive much deeper snowfalls than their low elevations might suggest.
In some years a big fall of snow can come as early as late October, only to be followed by warmer temperatures and heavy rain. These “rain on snow” events can cause serious flooding. Maintaining the forest cover is essential to controlling runoff.
The seasons themselves tend to occur later in the marine influenced Cascades than in other mountain ranges, since it takes a long time for ocean waters to heat and cool. This means that real summer often doesn't start until July, but can extend into early October. Winter is similarly delayed, with heaviest snow accumulations not usually seen until March or even early April. Springtime is the signature season of the Cascades, and on the west side can last nearly half the year, from February (in lowlands,) until the beginning of July. On the east side, many lower elevation grasslands don't fully green up until the beginning of May, but almost everywhere receives much more sun than the west side, and more warmth in summer.
Weather fronts can often arrive daily from late fall through early spring in the Cascades. Although most years see stretches of clear winter skies, there are inevitably many extended periods of dark, grey, wet weather. Combined with the short, eight hour winter days of latitude 47+ degrees north, this can make the wintertime Cascades a dreary place for those who long for light and sun, especially from November through January. On December 21st, the sun climbs no higher than 19 degrees above the southern horizon at noon – about the width of an outstretched hand. Valleys where mountains block the southern sky make things even worse.
But by the first of February, the days are noticeably and undeniably longer and the Big Dark of winter is losing its grip. On the lower west side at least, some plants begin growing and birds begin practicing their singing. Although winter weather patterns can persist into April, rapidly lengthening days soon make the gloom of winter a fading memory. The sun is up for sixteen hours a day in June and July, with even north facing slopes getting plenty of sun. Long lingering twilights last until 10 p.m., and even the most melancholy souls start finding the world to be a pleasant place.
From the lush green west, to the savannahs and semi-arid steppe grasslands of the east, the look and feel of landscapes is determined largely by rainfall amounts. But those numbers don't always tell the complete story. From the western front of the range, and inland for a widely varying number of miles, summertime marine clouds can keep things from drying out even in periods of little rain. When these clouds meet the mountain forests, fog drip can contribute substantial moisture to the trees. The number of days with these clouds diminishes with every mile east from the western mountain front. Thus, places such as the Beckler valley and lands east of it near Skykomish, while still receiving high annual rainfall, are sunnier during the summer than places to the west and forests there tend to be a little more open and less brushy.
The pattern of Cascades rainfall is seasonal, falling mostly from late October to early May. Snowline varies with temperature, with areas above 2500 feet receiving considerable snowfall most winters. Snow levels in weather forecasts tend to be accurate for the western mountain front only. Farther into the mountains snowlines are usually lower, and valleys penetrating deeply into the mountains receive much deeper snowfalls than their low elevations might suggest.
In some years a big fall of snow can come as early as late October, only to be followed by warmer temperatures and heavy rain. These “rain on snow” events can cause serious flooding. Maintaining the forest cover is essential to controlling runoff.
The seasons themselves tend to occur later in the marine influenced Cascades than in other mountain ranges, since it takes a long time for ocean waters to heat and cool. This means that real summer often doesn't start until July, but can extend into early October. Winter is similarly delayed, with heaviest snow accumulations not usually seen until March or even early April. Springtime is the signature season of the Cascades, and on the west side can last nearly half the year, from February (in lowlands,) until the beginning of July. On the east side, many lower elevation grasslands don't fully green up until the beginning of May, but almost everywhere receives much more sun than the west side, and more warmth in summer.
Weather fronts can often arrive daily from late fall through early spring in the Cascades. Although most years see stretches of clear winter skies, there are inevitably many extended periods of dark, grey, wet weather. Combined with the short, eight hour winter days of latitude 47+ degrees north, this can make the wintertime Cascades a dreary place for those who long for light and sun, especially from November through January. On December 21st, the sun climbs no higher than 19 degrees above the southern horizon at noon – about the width of an outstretched hand. Valleys where mountains block the southern sky make things even worse.
But by the first of February, the days are noticeably and undeniably longer and the Big Dark of winter is losing its grip. On the lower west side at least, some plants begin growing and birds begin practicing their singing. Although winter weather patterns can persist into April, rapidly lengthening days soon make the gloom of winter a fading memory. The sun is up for sixteen hours a day in June and July, with even north facing slopes getting plenty of sun. Long lingering twilights last until 10 p.m., and even the most melancholy souls start finding the world to be a pleasant place.