The strongly-jointed Humbug Spires...

near Butte, Montana offer a myriad of easy to moderate rock climbing routes on a smooth, spheroidally weathered granite.

Quartz monzonite of Cretaceous age (145-66 Ma) that comprises the Boulder batholith south of Butte, Montana. Orthoclase and plagioclase feldspars and quartz are the lighter minerals with accessory biotite and hornblende constituting the dark minerals.

This cobbly terrace edge remains stable...

after the dry winter and spring, with no evidence of any unraveling or failure whatsoever along the length of the escarpment. Castle Creek, slightly off the image to the right, is not likely to undercut this sedimentary terrace anytime soon. The singletrack remains safe to cruise.

The mighty tamarisk leaf-eating beetle...

caught in the act of defoliating a tamarisk on my property in Castle Valley. Large swaths of the invasive tamarisk along the Colorado River are being stressed this year, likely due to the widespread emergence of the tiny beetle following a very mild winter. If one listens closely you can hear them munching away. Go, beetle, go!

Tamarisk leaf-eating beetle (Diorhabda elongata), approximately 5 mm long.

Let’s get small: Macro image of a molting beetle. Look closely.

This beetle was introduced at Potash and at Dewey Bridge in 2004 as an experiment in biocontrol but it never fully eradicated the tamarisk along the riparian corridor, though this year they are very heavily stressed, likely aided by the hot and dry weather this spring and early summer.

Stressed tamarisk on both sides of the Colorado River upstream of Big Bend.

Colorado River upstream of Take Out Boat Ramp showing highly stressed tamarisk on both banks, yet the voracious beetle has left the gambel oaks, cottonwoods, willows and sandstone (!) untouched.

Danger on the trail...

early this morning when this unusually reddish rattler became annoyed and clearly announced its presence as I rolled by on the singletrack.

Hopi rattlesnake (Crotalus viridis nuntius), a subspecies of the prairie rattlesnake.

UPDATE: From Chris, a local BLM biologist: “Hopi rattlesnake makes sense for the color and smaller size. The taxonomy has changed recently so the subspecies is no longer recognized and is instead considered a dwarf variant of the prairie rattler.“

The guts of the Moab Fault...

exposed for all to see near the entrance to Arches National Park, just above the Visitors Center. A chunk of the Moenkopi Formation is trapped in the brecciated zone in between a pair of extensional faults (yellow lines). More than a half-mile of vertical displacement has occurred across this zone, that is, the Entrada Sandstone lies considerably higher in the stratigraphic section than the Honaker Trail Formation, so the relative offset is UP on the left and DOWN on the right across the fault zone in the view seen below.

View is towards the northwest. Note the tour bus on the park road on the right side of image. Yellow lines are normal faults with downthrown blocks on the right side of each.

An exploding population of squirrels...

has invaded our high desert community this spring, the most I have ever seen in 22 years. A local litter has just begun to venture out and they have all discovered the ground feeding stations. Super cute but destructive varmints, especially around the house.

Juvenile rock squirrel (Otospermophilus variegatus).

Quite a difference overnight...

in air quality as a persistent smoky airmass clears the canyons, seen here in comparative images into Professor Valley from a high vantage point on my daily ride.

THE DAY BEFORE around 7:45 am MDT.

TODAY around 8:00 am MDT where one can easily spy Fisher Towers six miles (9.6 km) away.

Summer solstice triple sunrise...

as captured this morning from the east end of Buchanan Lane in Castle Valley. The sun rises (#1) and is eclipsed by Baby Carriage Rock, it rises (#2) again and is eclipsed by Castleton Tower, only to rise (#3) a final time to mark the longest day of the year. It’s gonna be hot, too.

Composite of three stacked images, captured between 6:52 am and 7:41 am MDT.

UPDATE: This image is highlighted in this week’s Castle Valley Comments.

A gorgeous but poisonous southwestern plant...

that expresses enormous white blossoms larger than the palm of your hands, sacred datura is sometimes used as a narcotic and hallucinogen by Native Americans.

Sacred datura (Datura wrightii) in Lions Park.

Jimson Weed, oil on linen by Georgia O’Keeffe, 1936. Image courtesy Indianapolis Museum of Art.

A highly hazy horizon...

nearly obscures Castle Valley in the distance, likely due to wildfires burning near Bryce Canyon and in northern Arizona. Here’s the view across the sandstone expanse of Arches National Park caught early this morning from the Moab Brands mountain bike trail system.

Parriott Mesa, the Priest & Nuns, Castleton Tower and Adobe Mesa are all visible 15.5 miles (~25 km) away from this vantage point on the Moab Brands mountain bike trail system.

Priming and painting...

one of the larger missiles in the arsenal during these hot days with low humidity.

The Apogee Zephyr is a four inch diameter rocket that flies with a 38 mm engine mount and should easily get to a mile high.

The Zephyr twins, the larger of which still needs black paint on the nose cone and a final clear coat, but it’s ready to fly. The smaller has flown frequently on “D” and “E” rocket engines to nearly 1,000 ft (~300 m).