Ticks Down, Mosquitoes Up

If you’ve managed to get on the trails super early or super late in the day during this heat wave, it’s no news that mosquitoes are VERY active right now in this heat. The good news is that the tick activity decreases dramatically.

Check out this excerpt from an amazing online public health newsletter Your Local Epidemiologist. Started during COVID, this factual data-driven email newsletter (or substack) covers what you need to know (including another of today’s pieces on cyclospora). It is well worth your subscription to the email/substack (and donation if you are able).

Excerpt from Your Local Epidemiologist newsletter, July 14, 2026

Katelyn Jetelina and Marissa Donnelly, PhD

“Ticks are backing off

We’re well on our way down for tick season. Activity tends to drop off as we move deeper into the heat of summer.

Source: CDC; Annotated by Hannah Totte at Your Local Epidemiologist

Why? Ticks are prone to drying out, so in peak summer heat they retreat into moist, shaded leaf litter rather than questing (climbing grass to grab a host), which reduces host-seeking activity even if the tick population hasn’t shrunk. This dip also lines up with the tick life cycle: nymphs, responsible for most Lyme transmission, peak in late spring/early summer, then quiet down in the hottest weather before adults pick back up in fall.

Mosquitoes taking over

As ticks recede, mosquitoes take over and with them, the rare diseases they can carry. The most common one in the U.S. is West Nile.

Peak mosquito season is still about a month out, but the CDC is already flagging an unusually early surge in West Nile virus (WNV) activity this year. They have flagged 48 cases across 23 states detecting the virus, which is more than five times the historical average for this point in the season.

Source: CDC. Annotated by Hannah Totte at Your Local Epidemiologist

What this means for you: Most people infected with WNV never even know it because ~80% have no symptoms. But older adults and those who are immunocompromised can develop serious neurological illness. Start being consistent with using an EPA-registered repellent (with DEET or picaridin), dumping standing water around your home, and using screens at dusk and dawn.

Your Local Epidemiologist (YLE) comprises a team of experts, ranging from physicians to immunologists to epidemiologists to nutritionists, working together with one goal: to “translate” ever-evolving public health science so that people are well-equipped to make evidence-based decisions. The YLE suite of newsletters reaches over 475,000 people across more than 132 countries. This newsletter is free to everyone, thanks to the generous support of fellow YLE community members.” 

Stay cool and safe out there and see you on the trails.

Driftless Flooding

Beaver Creek Valley State Park creek July 2, 2026.
The park is currently closed
Image - Minnesota State Parks and Trails

The northeast Iowa, southwest Wisconsin, southeast Minnesota region has had a number of heavy, slowly moving storms over the past three days with significant acumulated rainfall amounts (4-10 inches). 

Creeks, streams and rivers have topped their banks throughout the region. Both low-lying and bluffside fields, roads, bridges and trails in some community, county and state parks have suffered damage or been partially or fully washed out.

More heavy rain and storms are predicted through Friday and possibly into Saturday.

Be sure to check ahead for park and trail closures on park websites before going through with your holiday hiking plans. And be safe out there.

Naturalist's Corner - Why Leaves Change Color

Clonal aspen stand, CO

Returning home from an extended October hiking trip in the Southwest last year, I was struck by the riot of colors that greeted me in our Driftless area. While I was impressed by the beautiful displays of gold and yellow of the aspen stands (all clones of single root systems) out west, I was worried I'd be too late to see the diverse fall colors that the Driftless area forests display.

Not to worry.

I was delighted to find that colors were just beginning to peak. Rather than large swaths of trees in the same color, we have a veritable party of different colors going vertically up the bluffs as you drive along the Mississippi River.

And it got me wondering...what sparks that change?  

It's not just one thing. The weather, the length of days and the individual tree's pigments all combine to create the color palette and timing. 

Each tree species has unique colors that depend on pigments already present in the leaf. For trees with yellow, orange and brown fall pigments (carotenoids), those colors are already in the leaves along with  the green chlorophyll during spring and summer. The chlorophyll masks these pigments during the summer. As the leaf prepares for winter, chlorophyll production slows and stops. That's when the bright yellows and oranges appear.

For trees that display more red and purple (anthocyanins), that pigment is produced in fall when excess sugar gathers in leaf cells.

This is usually preceded in August with a gradual lightening - or to my eyes, slight greying - of the deeper green colors of early summer as chlorophyll slows.

The shorter length of the day and less sunlight triggers leaf cells to start building up in the stem end, trapping the sugars and eventually sealing off the stem (when that happens, the leaf falls).

Finally the weather - sunny days and cool nights help create the most colorful leaves.  If there has been abundant rain in spring and summer to produce plenty of sugar for the trees, the colors will tend to be more brilliant. Drought and drier summers and fall, produce less sugar and can dull the colors. 

Driftless area states have "Fall Color-Finding" sites that keep you updated on the peak and past-peak times of autumn leaf changes:

• Minnesota
• Wisconsin
• Iowa

You can read more details about this process, at the US Forest Service webpage  and an interesting article from the November 1, 2024 edition of the Washington Post exploring the annual life cycle of a leaf and the effect our changing climate has on deciduous trees.

This short video produced on October 13, 2020 by Minnesota Master Naturalists for their Trail Tuesday series, goes through the process.

Check out my recommendations for favorite fall color hikes in the Driftless.

See you on the trails!

Fall Hiking - Staying Safe

On a 90F August day, it's a bit hard to wrap my head around the concept of autumn and fall. But the calendar and back-to-school sales alert me that, yes, September is just around the corner.

I am a huge fan of fall hiking. The cooler temps and frost slow and then stop most gnats and mosquitos on the trail (aah, bliiss). That same coolness makes strenuous hikes more comfortable. 

The colorful leaf party that the trees get together and throw for us is a welcome farewell to summer's green lushness. 

Late November hiking in IA's
Yellow River Forest

The dying back of brush in trails makes hiking easier as well. And as the leaves fall, geological formations, interesting rocks and caves are easily seen. 

The views at overlooks towards bluffs and rivers also are less obstructed and more expansive. I save my most challenging, steep hikes to tops of hikes with great rocks and views especially for these cooler months in late Sept through November.

But fall is also the time when hunting seasons open up in MN, WI and IA, the main areas I use. 

There are some easy precautions to take when you are out on the trails to stay safe:

Wear blaze orange or pink - hats, light vests and jackets in this color help hunters spot you. Neon yellow and neon green vests/shirts can also be helpful in small game and game bird seasons.

Pick destinations where hunting isn't allowed - make sure the park, conservancy land, state forest, SNA or area you are hiking in isn't posted as a hunting area. 

Be aware of private lands bordering your hiking area - while the park or area you are in may be posted "no hunting," bordering private lands might support hunters. Many public lands close trails nearby to protect you.

If you do decide to hike in an area where there is small game hunting, then...
...Stay on trails - during hunting seasons, many hunters who are off-trail in the woods are aware of where trails are. This isn't the time to go bushwhacking.

MN DNR

Know your state's hunting seasons - be aware of what seasons are open as well as where areas are that support different game animals and birds that are hunted near you.

• MN hunting seasons
• WI hunting seasons
• IA hunting seasons

Don't hike during firearm deer seasons - the pressure from "weekend warrior" hunters in those weeks is intense. Some of these hunters use extremely high powered rifles whose bullets can travel quite far. I take my safety seriously and let the deer hunters have the woods for their very short firearm seasons. 

Since my tri-state area has very few overlapping deer gun season weeks, one strategy I use is to head to a neighboring state when my state's deer gun season is on. It has worked well and lets me explore trails outside my state. While this might not work for everyone, for those along their state's borders, it's a great option.

With care, you can stay safe on your fall hikes by doing a bit of preparation. Those fall woods are worth the effort!

Scrambling on the rocks
in a Winona County blufftop

Images, unless noted - Marge Loch-Wouters

Sharing Winter Trails

Given weather forecasts for the next few days in the Driftless, it looks like we can seriously say winter is almost here.

And that reminds me of a few courtesy and safety issues when hiking/snowshoeing trails groomed for cross-country-skiers.

This graphic from the Washington Trail Association does a great job of reminding us how best to share the trails. Let's all preserve the integrity (and the hard work that goes into grooming) of these trails for our winter lovers on skis!

Hiking Safety in Fall

Last Saturday, September 23, waterfowl hunting season opened with a bang just at dawn in nearby wetlands near our Minnesota home. Although hunting seasons occur throughout the year, fall is an especially big time for hunting. In both Minnesota and Wisconsin, archery and small and big game gun hunting gets started in mid-September and continues throughout most of the fall.

As hikers, we often find ourselves in areas like Wildlife Management Areas (WMA's), land conservancies or other public lands like county or state forests where hunting is allowed. How do we keep safe?

One of the easiest steps you can take is making sure you do your fall hiking with an item of blaze orange or blaze pink on your head and/or above your waist. By wearing a hat, vest, or shirt in those colors, you reduce your chance of accidents tremendously. It's best to purchase these items in the summer when you can find a variety of choices and weights for the clothing. Once the hunting seasons start, very little stock is left for you to choose from.

We also add yellow vests that we can put over our coats  Combined with our blaze orange hats it gives us extra peace of mind. 

While some people also suggest bright colors, the gold standard remains blaze orange and pink. Hunters are looking for those colors on the trails and those colors are your best bet to protect yourself.

You can also consider limiting your hikes to state and city parks during this period. Be aware that these parks often border private land or other state lands where hunting is allowed. Sometimes state parks will close trails that border on active fall hunting lands. 

Know where you are going and check ahead if possible to see if hunting is allowed. Sometimes parks or natural areas will put up notices on their websites or Facebook pages to help guide you.

Year-round hiking is tremendously fun. With a few protective garments, you can feel more comfortable and safer in autumn during hunting season.

Wildfires and Hiking

It looks like we in the Driftless region (as well as others in the eastern northern tier states) may be in for a long summer of wildfire smoke. The Canadian fires just don't create a haze that obscures things far away. Whenever levels of wildfire smoke are high, that very same far-off haze is affecting the air immediately surrounding us and that we are breathing.

While that, of course, seems obvious, if you are also exercising or hiking with increased respiration, you are also increasing the volume of particulate matter that you are inhaling. Levels of PM2.5 are the wildfire particles of particular concern.

There were plenty of comments from campers, hikers, runners and bikers on social media in MN over Memorial Day weekend when many parts of the state experienced high alert days for very poor air quality. People recreating outside reported itchy burning eyes; sore throats, persistent coughs and some reported feeling pressure in their chests. 

There are two very easy things we can do to help protect our lungs and health when hiking and breathing hard on poor air quality days:

1. Be aware of the air quality daily. The EPA (Environmental Protection Agency) has a free website and app, AirNow.gov that lets you check air quality in real time plus a five day forecast; maps tracking smoke; whether the air quality is affected by ozone or wildfires and suggestions for when to be cautious if we are in an at-risk group. Just input your zipcode or the zipcode of where you plan to hike and voila.

2.  Have a KN95 or an N95 mask along on hikes, just in case. While masks are not super comfortable in summer, I note that hikers have managed to continue hikes with soaked boots after stream crossings; no raincoat in a downpour; not enough bug dope while the mosquitoes and deerflies swarm; doinked knees and ankles and elbows and noses and, well, whatever befalls them. Most of us come out bragging at the end of an adverse/uncomfortable hike despite the discomfort. I think a mask is a doable thing to protect our health. We can do it!

Check the resources below for additional information on how to protect yourself.

Resources

The Wildfire Smoke May Be Gone. But the Health Threat Remains. Wen, Leana S. Washington Post, June 12, 2023 A very good, science-based article that cites research on the effects of wildfire smoke. You can access the article for free by putting in your email address.

Wildfire smoke, COVID-19, and striking comparisons. Jetalina, Katelyn. Your Local Epidemiologist. Newsletter, June 9, 2023. A very good article that is science-based and points out the dangers of wildfire smoke and the need to mask up on high alert days.