Looks like these spikes happen anywhere from zero times per day (two multi-day episodes in the past month) to once or twice per day. And since 1) Whirligig is known to have erupted on the date of one of the spikes; and 2) somebody earlier this season mentioned seeing some sort of "abortedc" eruption by Whirligig, I shall posit that those spikes are indeed caused by Whirligig. ( A ground squirrel is somewhat less likely, but don't discount those pesky bears.) Scott Bryan In a message dated 8/22/2013 6:48:19 A.M. US Mountain Standard Time, jakefrisbee at yahoo.com writes: In the attached graph, you can see the temperature spike at about 1500 on July 29, 2013. There is a Geysertimes.org report of Whirligig Geyser at 2005 ie on July 29 from Craig Munson. -------------- next part -------------- An HTML attachment was scrubbed... URL: </geyser-list/attachments/20130822/378eb0db/attachment.html>