“bank full” – One month’s rain in 12 hours

Tropical Wave exceeds model predictions; NEMO forecasts more rain.

By William Ysaguirre (Freelance Writer)

BELIZE CITY, Mon. July 13, 2026

   The extreme weather event and heavy rainfall that fell on Belmopan and caused the unprecedented flooding in the Cayo District over the weekend exceeded the best model predictions, Chief Meteorologist Ronald Gordon admitted in a virtual media briefing Monday afternoon, July 13, as he warned the country of more rain expected later Monday night into Tuesday, July 14.

   A strong tropical wave system brought the rain, which was supported by a strong lower-level jet and strong upper-level currents, which dumped 273.4 mm of rain (10.8 inches) on Belmopan between midnight Friday to midday Saturday, while nearby La Gracia area received 8.5 inches, and the Hershey station on the Hummingbird Highway also reported 8.4 inches of rain. To put that in context, Belmopan averages about 245 mm of rain for the entire month of July; so, the extreme rainfall from the tropical wave dumped more rain on the Garden City in 12 hours than it normally receives in an entire month! This did not break the monthly record, as Belmopan received 334 mm (13.1 inches) of rain in June 2002; but the 12-hour downpour, outside of a hurricane, is likely unprecedented.

   The actual rainfall far exceeded the model, which had only predicted 2-3 inches of rain, and the daily flood forecast prepared by the National Hydrological Service at 3:00 p.m. Friday afternoon had only warned of possible flash-floods in the area of the Sibun Forest Reserve east of Cotton Tree and along the Coastal Highway over the next 36 hours. Gordon predicted more showers on Tuesday and into Tuesday night, especially over the southern part of the country, but only a moderate 2-3 inches of rain is anticipated, although he acknowledged that the model which the Met Service was using could not calculate possible extreme events.

   The National Hydrological Service monitors the Belize River watershed, and for the wider Belmopan area, the measuring station at More Tomorrow showed a rise from 1.8 meters on Friday to 7.55 meters on Monday, July 13, chief hydrologist Tenneille Hendy reported. On Sunday, July 12, it crested above 11 meters, which the gauge could not measure, as it only goes up to 11 meters, which was the previous historical record high.

   In the Sibun River Basin, there was a linear increase in water level of 3.5 meters, while in the Sittee River Basin, the gauge recorded an increase in water level from 1.5 meters on Friday, July 10, to 7.7 meters at 6:00 a.m., July 11. This water is now flowing downstream and according to the gauge at Double Run near Sandhill, the river is at “bank full” level, while the Sibun River has exceeded “bank full”.

   The Belmopan Emergency Operation Center was activated to monitor the situation in the Belmopan area and assess the impact of the floods, to identify and direct assistance to those most in need, coordinator Major Daniel Mendez of the National Emergency Management Organization (NEMO) reported. NEMO is preparing the Belize Rural Emergency Center to manage any flooding they may see, and he warned farmers and other residents of the River Valley that they should make appropriate preparations to protect livestock and protect crops where possible, and to secure their household items against the anticipated flood levels that are now progressing downstream. He encouraged families living in flood prone areas to secure their personal documents.

   Gordon acknowledged that their best model predictions could not foresee the extremely heavy rainfall experienced. NEMO opened the Belmopan emergency shelters, but very few people accessed the shelter, Mendez noted.

   Hendy warned that while only 2 – 3 inches of rain is forecast for Tuesday, the river at Bermudian Landing and Double Run is already at “bank full”. More Tomorrow saw a record high of 10 meters which has not receded, so River Valley residents can expect the river to rise and flood, as the floodwaters flow downstream. He said that the volume of water dictates the velocity of flow, and normally, flood levels would have been expected to take 3 days to reach the levels which have been seen downstream in a space of 24 hours, indicating that the water is moving a lot faster than expected. All this water will eventually flow into the Crooked Tree lagoon, which is a retention reservoir, Hendy explained, but there are also many smaller creeks and smaller lagoons into which the water will flow first, so Hendy anticipates that the Crooked Tree lagoon is unlikely to flood over the causeway in the next couple days.