diff --git a/Project.toml b/Project.toml
index 3e497eaf6e..27d7bbd653 100644
--- a/Project.toml
+++ b/Project.toml
@@ -41,7 +41,7 @@ ArtifactWrappers = "0.2"
 BSON = "0.3.9"
 CSV = "0.10.14"
 CUDA = "5.5"
-ClimaComms = "0.6"
+ClimaComms = "0.6.2"
 ClimaCore = "0.14.19"
 ClimaDiagnostics = "0.2.10"
 ClimaParams = "0.10.2"
diff --git a/docs/make.jl b/docs/make.jl
index 584e9e74d8..06649b24bc 100644
--- a/docs/make.jl
+++ b/docs/make.jl
@@ -52,14 +52,15 @@ include("list_diagnostics.jl")
 pages = Any[
     "Home" => "index.md",
     "Getting Started" => "getting_started.md",
+    "Repository structure" => "folderstructure.md",
     "Tutorials" => tutorials,
     "Standalone models" => standalone_models,
     "Diagnostics" => diagnostics,
     "Leaderboard" => "leaderboard/leaderboard.md",
     "Restarts" => "restarts.md",
-    "Contribution guide" => "Contributing.md",
-    "Repository structure" => "folderstructure.md",
+    "Misc. utilities" => "shared_utilities.md",
     "APIs" => apis,
+    "Contribution guide" => "Contributing.md",
 ]
 
 mathengine = MathJax(
diff --git a/docs/src/shared_utilities.md b/docs/src/shared_utilities.md
new file mode 100644
index 0000000000..3562515b35
--- /dev/null
+++ b/docs/src/shared_utilities.md
@@ -0,0 +1,36 @@
+# ClimaLand Shared Utilities
+
+## State NaN Counter - `count_nans_state`
+We have implemented a function `count_nans_state` which recursively goes
+through the entire state and displays the number of NaNs found for each state
+variable. This function is intended to be used to debug simulations to
+determine quantitatively if a simulation is stable.
+
+If NaNs are found for a particular variable, this will be displayed via
+a warning printed to the console. The `verbose` argument toggles whether
+the function prints output when no NaNs are found.
+
+If a ClimaCore Field is provided as `mask`, the function will only count NaNs
+in the state variables where the mask is 1. This is intended to be used with
+the land/sea mask, to avoid counting NaNs over the ocean. Note this assumes
+the mask is 1 over land and 0 over ocean.
+
+This function does not distinguish between surface or subsurface
+variables, so a variable defined on the subsurface will display more NaNs
+than one defined on the surface, even if they are NaN at the same
+spatial locations in the horizontal.
+
+### Usage examples
+This function can be used to inspect the state after a simulation finishes
+running by calling `count_nans_state(sol.u[end])`.
+
+This function can be used throughout the duration of a simulation by
+triggering it via a callback. The `NaNCheckCallback` is designed for this
+purpose, and can be set up as follows:
+```julia
+nancheck_freq = Dates.Month(1)
+nancheck_cb = ClimaLand.NaNCheckCallback(nancheck_freq, start_date, t0, Δt)
+```
+and then included along with any other callbacks in a `SciMLBase.CallbackSet`.
+
+Please see our longrun experiments to see examples of this callback in action!
diff --git a/experiments/long_runs/bucket.jl b/experiments/long_runs/bucket.jl
index a43485a607..8c9ba902a2 100644
--- a/experiments/long_runs/bucket.jl
+++ b/experiments/long_runs/bucket.jl
@@ -144,7 +144,11 @@ function setup_prob(t0, tf, Δt; outdir = outdir, nelements = (101, 7))
     diag_cb = ClimaDiagnostics.DiagnosticsCallback(diagnostic_handler)
 
     driver_cb = ClimaLand.DriverUpdateCallback(updateat, updatefunc)
-    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb)
+
+    nancheck_freq = Dates.Month(1)
+    nancheck_cb = ClimaLand.NaNCheckCallback(nancheck_freq, start_date, t0, Δt)
+
+    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb, nancheck_cb)
 end
 
 function setup_and_solve_problem(; greet = false)
diff --git a/experiments/long_runs/land.jl b/experiments/long_runs/land.jl
index a1c15fc2fa..f9541a983a 100644
--- a/experiments/long_runs/land.jl
+++ b/experiments/long_runs/land.jl
@@ -374,7 +374,10 @@ function setup_prob(t0, tf, Δt; outdir = outdir, nelements = (101, 15))
     diag_cb = ClimaDiagnostics.DiagnosticsCallback(diagnostic_handler)
 
     driver_cb = ClimaLand.DriverUpdateCallback(updateat, updatefunc)
-    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb)
+
+    nancheck_freq = Dates.Month(1)
+    nancheck_cb = ClimaLand.NaNCheckCallback(nancheck_freq, start_date, t0, Δt)
+    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb, nancheck_cb)
 end
 
 function setup_and_solve_problem(; greet = false)
diff --git a/experiments/long_runs/land_region.jl b/experiments/long_runs/land_region.jl
index 129cb24755..4f638983b4 100644
--- a/experiments/long_runs/land_region.jl
+++ b/experiments/long_runs/land_region.jl
@@ -389,7 +389,10 @@ function setup_prob(t0, tf, Δt; outdir = outdir, nelements = (10, 10, 15))
     diag_cb = ClimaDiagnostics.DiagnosticsCallback(diagnostic_handler)
 
     driver_cb = ClimaLand.DriverUpdateCallback(updateat, updatefunc)
-    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb)
+
+    nancheck_freq = Dates.Month(1)
+    nancheck_cb = ClimaLand.NaNCheckCallback(nancheck_freq, start_date, t0, Δt)
+    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb, nancheck_cb)
 end
 
 function setup_and_solve_problem(; greet = false)
diff --git a/experiments/long_runs/snowy_land.jl b/experiments/long_runs/snowy_land.jl
index 43e526b8d5..35c8b8a296 100644
--- a/experiments/long_runs/snowy_land.jl
+++ b/experiments/long_runs/snowy_land.jl
@@ -396,7 +396,11 @@ function setup_prob(t0, tf, Δt; outdir = outdir, nelements = (101, 15))
     end
     report_cb = SciMLBase.DiscreteCallback(every1000steps, report)
 
-    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb, report_cb)
+    nancheck_freq = Dates.Month(1)
+    nancheck_cb = ClimaLand.NaNCheckCallback(nancheck_freq, start_date, t0, Δt)
+
+    return prob,
+    SciMLBase.CallbackSet(driver_cb, diag_cb, report_cb, nancheck_cb)
 end
 
 function setup_and_solve_problem(; greet = false)
diff --git a/experiments/long_runs/soil.jl b/experiments/long_runs/soil.jl
index fc9fa3ebb6..ced7621b37 100644
--- a/experiments/long_runs/soil.jl
+++ b/experiments/long_runs/soil.jl
@@ -215,7 +215,10 @@ function setup_prob(t0, tf, Δt; outdir = outdir, nelements = (101, 15))
     diag_cb = ClimaDiagnostics.DiagnosticsCallback(diagnostic_handler)
 
     driver_cb = ClimaLand.DriverUpdateCallback(updateat, updatefunc)
-    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb)
+
+    nancheck_freq = Dates.Month(1)
+    nancheck_cb = ClimaLand.NaNCheckCallback(nancheck_freq, start_date, t0, Δt)
+    return prob, SciMLBase.CallbackSet(driver_cb, diag_cb, nancheck_cb)
 end
 
 function setup_and_solve_problem(; greet = false)
diff --git a/src/shared_utilities/utils.jl b/src/shared_utilities/utils.jl
index 68740bf4b2..5f27ddad3e 100644
--- a/src/shared_utilities/utils.jl
+++ b/src/shared_utilities/utils.jl
@@ -3,7 +3,7 @@ import SciMLBase
 import ClimaDiagnostics.Schedules: EveryCalendarDtSchedule
 import Dates
 
-export FTfromY
+export FTfromY, count_nans_state
 
 """
      heaviside(x::FT)::FT where {FT}
@@ -320,7 +320,7 @@ function CheckpointCallback(
 
     if !isnothing(dt)
         dt_period = Dates.Millisecond(1000dt)
-        if !isdivisible(checkpoint_frequency_period / dt_period)
+        if !isdivisible(checkpoint_frequency_period, dt_period)
             @warn "Checkpoint frequency ($(checkpoint_frequency_period)) is not an integer multiple of dt $(dt_period)"
         end
     end
@@ -492,3 +492,110 @@ function isdivisible(
     # have any common divisor)
     return isinteger(Dates.Day(1) / dt_small)
 end
+
+"""
+    count_nans_state(state, mask::ClimaCore.Fields.Field = nothing, verbose = false)
+
+Count the number of NaNs in the state, e.g. the FieldVector given by
+`sol.u[end]` after calling `solve`. This function is useful for
+debugging simulations to determine quantitatively if a simulation is stable.
+
+If this function is called on a FieldVector, it will recursively call itself
+on each Field in the FieldVector. If it is called on a Field, it will count
+the number of NaNs in the Field and produce a warning if any are found.
+
+If a ClimaCore Field is provided as `mask`, the function will only count NaNs
+in the state variables where the mask is 1. This is intended to be used with
+the land/sea mask, to avoid counting NaNs over the ocean. Note this assumes
+the mask is 1 over land and 0 over ocean.
+
+The `verbose` argument toggles whether the function produces output when no
+NaNs are found.
+"""
+function count_nans_state(
+    state::ClimaCore.Fields.FieldVector;
+    mask = nothing,
+    verbose = false,
+)
+    for pn in propertynames(state)
+        state_new = getproperty(state, pn)
+        @info "Checking NaNs in $pn"
+        count_nans_state(state_new; mask, verbose)
+    end
+    return nothing
+end
+
+function count_nans_state(
+    state::ClimaCore.Fields.Field;
+    mask = nothing,
+    verbose = false,
+)
+    # Note: this code uses `parent`; this pattern should not be replicated
+    num_nans =
+        isnothing(mask) ? round(sum(isnan, parent(state))) :
+        round(sum(isnan, parent(state)[Bool.(parent(mask))]; init = 0))
+    if isapprox(num_nans, 0)
+        verbose && @info "No NaNs found"
+    else
+        @warn "$num_nans NaNs found"
+    end
+    return nothing
+end
+
+"""
+    NaNCheckCallback(nancheck_frequency::Union{AbstractFloat, Dates.Period},
+                        start_date, t_start, dt)
+
+Constructs a DiscreteCallback which counts the number of NaNs in the state
+and produces a warning if any are found.
+
+# Arguments
+- `nancheck_frequency`: The frequency at which the state is checked for NaNs.
+  Can be specified as a float (in seconds) or a `Dates.Period`.
+- `start_date`: The start date of the simulation.
+- `t_start`: The starting time of the simulation (in seconds).
+- `dt`: The timestep of the model (optional), used to check for consistency.
+
+The callback uses `ClimaDiagnostics.EveryCalendarDtSchedule` to determine when
+to check for NaNs based on the `nancheck_frequency`. The schedule is
+initialized with the `start_date` and `t_start` to ensure that it is first
+called at the correct time.
+"""
+function NaNCheckCallback(
+    nancheck_frequency::Union{AbstractFloat, Dates.Period},
+    start_date,
+    t_start,
+    dt,
+)
+    # TODO: Move to a more general callback system. For the time being, we use
+    # the ClimaDiagnostics one because it is flexible and it supports calendar
+    # dates.
+
+    if nancheck_frequency isa AbstractFloat
+        # Assume it is in seconds, but go through Millisecond to support
+        # fractional seconds
+        nancheck_frequency_period = Dates.Millisecond(1000nancheck_frequency)
+    else
+        nancheck_frequency_period = nancheck_frequency
+    end
+
+    schedule = EveryCalendarDtSchedule(
+        nancheck_frequency_period;
+        start_date,
+        date_last = start_date + Dates.Millisecond(1000t_start),
+    )
+
+    if !isnothing(dt)
+        dt_period = Dates.Millisecond(1000dt)
+        if !isdivisible(nancheck_frequency_period, dt_period)
+            @warn "Callback frequency ($(nancheck_frequency_period)) is not an integer multiple of dt $(dt_period)"
+        end
+    end
+
+    cond = let schedule = schedule
+        (u, t, integrator) -> schedule(integrator)
+    end
+    affect! = (integrator) -> count_nans_state(integrator.u)
+
+    SciMLBase.DiscreteCallback(cond, affect!)
+end
diff --git a/test/shared_utilities/utilities.jl b/test/shared_utilities/utilities.jl
index e44fbe8a16..c935760f31 100644
--- a/test/shared_utilities/utilities.jl
+++ b/test/shared_utilities/utilities.jl
@@ -2,7 +2,6 @@ using Test
 import ClimaComms
 ClimaComms.@import_required_backends
 using ClimaCore: Spaces, Geometry, Fields
-import ClimaComms
 using ClimaLand
 using ClimaLand: Domains, condition, SavingAffect, saving_initialize
 
@@ -256,3 +255,107 @@ end
         @test Y.subfields.subfield2 == Y_copy.subfields.subfield2
     end
 end
+
+@testset "count_nans_state, FT = $FT" begin
+    # Test on a 3D spherical domain
+    domain = ClimaLand.Domains.SphericalShell(;
+        radius = FT(2),
+        depth = FT(1.0),
+        nelements = (10, 5),
+        npolynomial = 3,
+    )
+
+    # Construct some fields
+    space = domain.space.subsurface
+    var1 = Fields.zeros(space)
+    var2 = Fields.zeros(space)
+    var3 = Fields.zeros(space)
+    fieldvec = Fields.FieldVector(var2 = var2, var3 = var3)
+
+    # Construct a FieldVector containing the fields and a nested FieldVector
+    Y = Fields.FieldVector(var1 = var1, fieldvec = fieldvec)
+
+    # Count and log the number of NaNs in the state (test verbose and non-verbose cases)
+    @test_logs (:info, "Checking NaNs in var1") (:info, "No NaNs found") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:info, "No NaNs found") (
+        :info,
+        "Checking NaNs in var3",
+    ) (:info, "No NaNs found") ClimaLand.count_nans_state(Y, verbose = true)
+
+    @test_logs (:info, "Checking NaNs in var1") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:info, "Checking NaNs in var3") ClimaLand.count_nans_state(
+        Y,
+    )
+
+    # Add some NaNs to the fields
+    # Note: this code uses `parent` and scalar indexing,
+    # which shouldn't be replicated outside of tests
+    ClimaComms.allowscalar(ClimaComms.device()) do
+        parent(var1)[1] = NaN
+        parent(var2)[1] = NaN
+        parent(var2)[2] = NaN
+    end
+
+    # Count and log the number of NaNs in the state (test verbose and non-verbose cases)
+    @test_logs (:info, "Checking NaNs in var1") (:warn, "1 NaNs found") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:warn, "2 NaNs found") (
+        :info,
+        "Checking NaNs in var3",
+    ) (:info, "No NaNs found") ClimaLand.count_nans_state(Y, verbose = true)
+
+    @test_logs (:info, "Checking NaNs in var1") (:warn, "1 NaNs found") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:warn, "2 NaNs found") (
+        :info,
+        "Checking NaNs in var3",
+    ) ClimaLand.count_nans_state(Y)
+
+    # Test with a mask
+    mask_zeros = Fields.zeros(space)
+    @test_logs (:info, "Checking NaNs in var1") (:info, "No NaNs found") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:info, "No NaNs found") (
+        :info,
+        "Checking NaNs in var3",
+    ) (:info, "No NaNs found") ClimaLand.count_nans_state(
+        Y,
+        mask = mask_zeros,
+        verbose = true,
+    )
+    @test_logs (:info, "Checking NaNs in var1") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:info, "Checking NaNs in var3") ClimaLand.count_nans_state(
+        Y,
+        mask = mask_zeros,
+    )
+
+    mask_ones = Fields.ones(space)
+    @test_logs (:info, "Checking NaNs in var1") (:warn, "1 NaNs found") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:warn, "2 NaNs found") (
+        :info,
+        "Checking NaNs in var3",
+    ) (:info, "No NaNs found") ClimaLand.count_nans_state(
+        Y,
+        mask = mask_ones,
+        verbose = true,
+    )
+
+    @test_logs (:info, "Checking NaNs in var1") (:warn, "1 NaNs found") (
+        :info,
+        "Checking NaNs in fieldvec",
+    ) (:info, "Checking NaNs in var2") (:warn, "2 NaNs found") (
+        :info,
+        "Checking NaNs in var3",
+    ) ClimaLand.count_nans_state(Y, mask = mask_ones)
+end