Dennis’ Tidbits


June 8, 2021

Back in 1997, Hurricane Guillermo kept it up for 31 days

Dennis 5The second tropical system of the 2021 hurricane season in the Eastern Pacific has come and gone in quick fashion. Her name was Blanca and she only lasted for a couple of days as a low-end tropical storm, not affecting our weather or surf, and did not pose any threat to any land mass. The Atlantic remains quiet at this time.

Here on Sunday, local ocean temps scratched and clawed their way back up into the mid-60s with even a 68-degree reading down in San Clemente. Normal for this date is about 64-66, so we’re right there.

A well-organized Eastern Pacific tropical system usually has a life span of around 7-10 days, but every once in a while there’ll be a real freak of a storm that seems to last forever, as was the case of Hurricane Guillermo in 1997, when a mega El Nino was in full swing. Guillermo held it together for a total of 31 days and traveled nearly 5,000 miles from start to finish. The monster hurricane set a record for the number of days it remained a Cat 5 storm. 

Here’s what went down: On July 26, 1997, Guillermo was born way down there just off the coast of Central America and immediately began to intensify rapidly. By the next day he was already a Cat 2 hurricane with winds of 100 mph as he began moving slowly to the WNW with a central pressure of 970 millibars. Water temps down there were nearly 90 degrees, adding extra fuel to Bill’s explosive development. (Guillermo is Spanish for Bill.) By the very next day, Bill had strengthened to a Cat 4 with a central pressure of 939 millibars as he crept slowly to the WNW at only 6 mph. 

On the morning of July 27, Guillermo was a monster Cat 5 with sustained winds of 162 mph, gusts up to 175, and a central pressure down to 907 millibars – and he was huge too, almost 650 miles across! For several more days he continued moving to the WNW at a snail’s pace for a storm at 6 mph, and on August 4 he entered our swell window, still a Cat 5 behemoth. His waves began to arrive on August 7 and because of his very slow forward speed, his epic swell lasted for a whole week. By August 12 he left our swell window and sped up as he was downgraded to a Cat 4 hurricane while setting his sights on Hawaii as he turned a little more to the west.

On August 18, Bill was still very much alive and only 250 miles ESE of the Big Island as hurricane warnings were posted for the entire Island chain that evening. Normally waters in that area are around 76 or 77 degrees, so any system that is approaching them will now be in an environment that is not conducive for maintaining its strength, but that year with the super El Nino, waters were very much hurricane-friendly at 83 degrees with little or no shear winds. So the door was open as Guillermo was as healthy as ever, still a low-end Cat 4 with winds up to 135 mph, as giant swells began invading the south shores and windward sides. 

At that point it looked like a surefire direct hit on the Islands by a major hurricane. Folks were still recovering from Cat 4 Iniki from five years prior in September of 1992, and don’t forget Iwa in November of 1982. Both of those were also a product of a strong El Nino. More on Guillermo and the wild 1997 season in Friday’s edition of Stu News. Until then have a great and healthy week!