Strawberry resident launches flood app based on the tides

The FloodRoute app showed current tide levels at 5.1 feet at 1:25 p.m. Jan. 22, with no flooding predicted (left), while its simulation mode at 9 feet projects 482 roads at risk countywide, with red markings indicating flooding along Highway 101, Strawberry and downtown Tiburon (right).

A Strawberry resident has developed and published a new iPhone app that predicts which Marin roads will flood based on tide heights — and it’s about to face its first major test.

Marc Hoag, 46, spent the early days of the new year working on the idea following flooding along the Tiburon Peninsula in early January. He shared a screenshot of his work-in-progress on Nextdoor, the hyperlocal social-media forum, asking neighbors if they’d find such an app useful.

The response was immediate, with more than 200 reactions and many commenters urging him to build the app.

Roughly 24 hours after sharing his idea, Hoag on Jan. 16 published FloodRoute, an iOS-only app that uses tide data from the National Oceanic and Atmospheric Administration, flood-zone data from the Federal Emergency Management Agency and road-elevation mapping to project which roads will flood.

The app faces its first real-world test this week. NOAA projects higher-than-normal king tides Jan. 29-Feb. 2, with high tides between 6.38 and 6.7 feet at the U.S. Army Corps of Engineers dock in Sausalito, peaking at 9:40 a.m. Jan. 31.

Read the complete story in our e-edition, or SUBSCRIBE NOW for home delivery and access to the digital replica.

Comment on this article on Nextdoor.