During routine flight over lake barryessa; a pilot reported observing a paraglider in excess of 3;00...

Narrative:

I was in a small fixed wing aircraft at 3;500 feet traversing to vacaville via over lake berryessa. As we were at cruise; [we] spotted a boat on the lake that had a line going up towards the sky. We then both observed a paraglider; connected to that boat at approximately 3;000 feet and around a mile to our 11 o'clock position. I then maneuvered to the right to gain distance from the paraglider. We then observed the paraglider continued to be towed up to at least 3;500 feet; where he was then released. As the paraglider descended; they were doing multiple aerobatics. I made numerous calls on the multi-lake frequency 122.9; but had no response from the boat or ground crews. There were also no notams listed for this activity nor is there anything denoted on sectional charts. Lake berryessa is a highly traveled air route for numerous VFR and IFR traffic. These paragliders present a serious risk; being towed over 3;000 feet with a tow line that is impossible for a pilot to see. A weekend flyer; traversing this area; would never expect to see this kind of paragliding activity.

Original NASA ASRS Text

Title: During routine flight over Lake Barryessa; a pilot reported observing a paraglider in excess of 3;000 feet while under tow from watercraft causing pilot to take evasive action.

Narrative: I was in a small fixed wing aircraft at 3;500 feet traversing to Vacaville via over Lake Berryessa. As we were at cruise; [we] spotted a boat on the lake that had a line going up towards the sky. We then both observed a paraglider; connected to that boat at approximately 3;000 feet and around a mile to our 11 o'clock position. I then maneuvered to the right to gain distance from the paraglider. We then observed the paraglider continued to be towed up to at least 3;500 feet; where he was then released. As the paraglider descended; they were doing multiple aerobatics. I made numerous calls on the multi-lake frequency 122.9; but had no response from the boat or ground crews. There were also no NOTAMs listed for this activity nor is there anything denoted on sectional charts. Lake Berryessa is a highly traveled air route for numerous VFR and IFR traffic. These paragliders present a serious risk; being towed over 3;000 feet with a tow line that is impossible for a pilot to see. A weekend flyer; traversing this area; would never expect to see this kind of paragliding activity.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1675760
Time
Date	201908
Local Time Of Day	0601-1200
Place
Locale Reference	NCT.TRACON
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft High Wing 1 Eng Fixed Gear
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	None
Flight Plan	None
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Instrument
Experience	Flight Crew Total 860
Events
Anomaly	ATC Issue All Types Airspace Violation All Types Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance
Miss Distance	Horizontal 1500 Vertical 500

During routine flight over lake barryessa; a pilot reported observing a paraglider in excess of 3;000 feet while under tow from watercraft causing pilot to take evasive action.