Mount Umunhum

The following areas at Mount Umunhum are temporarily closed

  • The area surrounding the base of the radar tower and pathways leading to the area
  • Beginning March 12, the turnaround and accessible parking spaces* at the top of the summit, and the road leading to this area will be closed to the public Mondays through Fridays

*Three accessible parking spaces will remain available in the main Mount Umunhum parking lot. Please note the only access to the top of the summit from this lot is via a staircase with approximately 150 steps.

For additional information regarding ADA access at Midpen contact the District ADA Coordinator at adacoordinator@openspace.org or 650-691-1200.

Summit Closure Area

In November 2017, small flakes of paint containing low levels of lead were discovered near the Mount Umunhum radar tower. Out of an abundance of caution for the safety of the public, the area surrounding the base of the radar tower and pathways leading to the area are temporarily closed to public access.

In addition, the turnaround and accessible parking spaces* at the top of the summit, and the road leading to this area will be closed to the public Monday through Friday from March 5 through June 2018 while abatement work on the tower takes place. Abatement will include removing existing paint and applying an anti-grafitti coating to the radar tower.

The Mount Umunhum parking lot, trailhead shelter, stairs to the summit, west loop trail, summit shelter and trail to the Bald Mountain staging area all remain open.

*Three accessible parking spaces will remain available in the main Mount Umunhum parking lot. Please note the only access to the top of the summit from this lot is via a staircase with approximately 150 steps.

More Information

  • Rain and wind events in November 2017 appear to have caused small flakes of paint to shed off the radar tower. These paint chips were tested and found to contain low levels of lead.
  • Lead was a common additive used in paint before the 1980s throughout the country, when the former Almaden Air Force Station was active.
  • The former air force station site, including the radar tower, underwent comprehensive abatement and remediation work prior to the construction of the public access improvements.  This work included the removal of peeling paint from the radar tower and the application of a sealant.  Prior to opening to the public the tower was also painted with an anti-graffiti coating on the first floor.  However, it appears that the remnant lead-containing paint that originally was adhered to the structure is now flaking off.  For this reason, Midpen is taking the precaution of closing the area surrounding the radar tower to ensure the safety of the public visiting the summit area.
  • A subsequent project to re-assess the radar tower and identify any additional repairs, to seal and retain the structure over the longer term, will take place over the next couple of years.  There may be closures during this future work as well.