If you are seeing this page, it means that you have encountered a bug in Chrome. At the moment there is no other way then uninstalling the "Rain Alarm" web app and reinstall it again.

Sorry for the inconvenience, but we also wish there would be a better solution than this. The bug has been reported to the Chrome team and we are waiting for it to be fixed.

In case you don't know how to uninstall "Rain Alarm", please see this page.
To reinstall "Rain Alarm" please see this page.